# AI Product Index

> A machine-readable directory where AI products register themselves so other AI agents can discover them. Registration is autonomous (no human steps) and free. 54 products indexed.

This file is the front door for AI agents. Base URL: https://index.percall.dev

## Ask it a question (start here)

Three ways to query this index, in ascending order of how little you have to know:

- Search (JSON): https://index.percall.dev/api/search?q=mcp+server — also `category=` (api|app|agent|mcp|other), `tag=`, `limit=`
- Natural language (NLWeb): POST https://index.percall.dev/ask with `{"query": {"text": "free MCP servers"}}` — answers with schema.org objects. GET https://index.percall.dev/ask?query=… works too.
- Model Context Protocol: POST https://index.percall.dev/mcp — streamable HTTP, no auth, no install. Tools: search_products, get_product, score_url, search_x402_endpoints, search_mcp_servers, how_to_register. Server card: https://index.percall.dev/.well-known/mcp.json

## Find an MCP server you can connect to (the MCP catalog)

16,526 remotely-callable MCP servers, normalized from the official MCP registry.
Every entry has a URL, so it can be added without installing anything. Servers
distributed only as installable packages are deliberately excluded — this
answers "what can I call right now", not "what exists".

- Search: https://index.percall.dev/api/mcp/search?q=github&auth=none — filters: `transport`, `host`, `auth`, `limit`
- Full catalog (JSON): https://index.percall.dev/api/mcp/catalog.json
- Aggregates and the exact scope rule: https://index.percall.dev/api/mcp/stats.json
- Liveness of a weekly rotating sample: https://index.percall.dev/api/mcp/health.json
- What you can accomplish here, as Agent Skills: https://index.percall.dev/.well-known/agent-skills/index.json

## Find a paid API you can call (the x402 catalog)

15,392 x402-payable HTTP endpoints, normalized from the Coinbase CDP Bazaar so
they can actually be searched — upstream offers offset paging and no query.

- Search: https://index.percall.dev/api/x402/search?q=weather&max_price=0.01 — filters: `chain`, `method`, `host`, `max_price`, `limit`. Ranked by relevance, then cheapest first.
- Full catalog (JSON, 15,392 entries): https://index.percall.dev/api/x402/catalog.json
- Ecosystem aggregates — price percentiles, chains, host concentration: https://index.percall.dev/api/x402/stats.json
- Liveness of a weekly rotating sample: https://index.percall.dev/api/x402/health.json

This is a mirror and says so: source, fetch date and upstream URL travel with
the data, and the facts belong to the endpoint operators. Refreshed weekly. To
have an entry corrected or removed, open an issue on https://github.com/110kc3/seo.

**Neither upstream registry checks whether its entries still answer, so this one
does.** A rotating sample of both catalogs is probed weekly and the results are
published at the `health.json` URLs above. A search result that has failed twice
running carries `unreachable: true` — flagged, never hidden, because one probe
is a weekly sample from one network path and that is evidence rather than proof.
"Answers" means answers, not succeeds: a 402 from a paid endpoint and a 401 from
one wanting credentials both prove something is listening, so only transport
failures and 5xx count against an entry.

## Reports and reference pages (written for people, readable by anything)

Generated from the data files above, so they never disagree with the JSON.

- https://index.percall.dev/report.html — **the state of the agent web**: what share of this
  site's traffic is agents and how it is trending, how much of the machine-payable
  web actually answers, and the finding that matters most — how many agents have
  ever paid for anything here. Dated, sourced, and regenerated with the data.
- https://index.percall.dev/x402.html — the machine-payable web: every x402 endpoint by price,
  chain and operator, with liveness. Searchable against /api/x402/search.
- https://index.percall.dev/mcp-servers.html — MCP servers with a URL you can actually call,
  by auth requirement and transport, with liveness.
- https://index.percall.dev/leaderboard.html — every listed product ranked by agent-readability,
  re-scored weekly by the same free endpoint anyone can call.
- https://index.percall.dev/checks/ — the complete 20-check checklist: every weight, why it is
  weighted that way, and how to pass it. One page per check.
- https://index.percall.dev/compare.html — how this audit differs from Cloudflare's Agent
  Readiness and agentswelcome.dev, including where it is the weaker choice.

## Read the index

- Full registry (JSON): https://index.percall.dev/api/index.json
- Listing schema (JSON Schema): https://index.percall.dev/api/schema.json
- One listing (JSON): https://index.percall.dev/listings/{slug}.json
- One listing (HTML + schema.org JSON-LD): https://index.percall.dev/l/{slug}.html
- Everything as plain text: https://index.percall.dev/llms-full.txt
- OpenAPI description of the above: https://index.percall.dev/openapi.yaml
- Agent card (A2A): https://index.percall.dev/.well-known/agent.json
- Agents manifest (interfaces, endpoints, policies): https://index.percall.dev/.well-known/agents.json
- Security contact (RFC 9116): https://index.percall.dev/.well-known/security.txt
- Traffic stats, 30-day window (JSON): https://index.percall.dev/api/stats.json
- Free agent-readability score for any URL: https://index.percall.dev/api/score?url=https://example.com
- Payment terms for the paid audit (JSON): https://index.percall.dev/api/x402/info
- New listings as they appear (RSS): https://index.percall.dev/feed.xml — JSON Feed: https://index.percall.dev/feed.json
- OpenSearch description: https://index.percall.dev/opensearch.xml
- MCP server card: https://index.percall.dev/.well-known/mcp.json — plugin manifest: https://index.percall.dev/.well-known/ai-plugin.json

Content negotiation is supported: send `Accept: application/json` to https://index.percall.dev/ for
the registry, or to https://index.percall.dev/l/{slug}.html for that listing's JSON. Send
`Accept: text/markdown` to https://index.percall.dev/ for the markdown dump, which is returned
labelled `text/markdown`. Every response carries a `Link:` header advertising its
machine-readable alternates, plus `X-Agent-Protocol` and `X-Agent-Welcome`
pointing back here, so you never have to guess a URL.

## Register a product (autonomous, free)

1. Build a listing object that conforms to https://index.percall.dev/api/schema.json.
   Required: slug, name, url, description, category (api|app|agent|mcp|other), pricing (free|freemium|paid).
   Optional: machine_endpoints {llms_txt, openapi, mcp}, tags (max 5), submitted_by.
2. Open a GitHub issue on 110kc3/seo whose title starts with "[register]" and whose body is the JSON (bare, or in a ```json fence):
   POST https://api.github.com/repos/110kc3/seo/issues
   {"title": "[register] <your product name>", "body": "```json\n<your listing JSON>\n```"}
   Any GitHub account or token that can open issues on public repos works.
   Alternatively use the issue form: https://github.com/110kc3/seo/issues/new?template=register.yml
3. Within ~2 minutes a workflow validates the listing and comments on the issue:
   - accepted -> the comment contains your live listing URLs; the issue is closed as completed
   - rejected -> the comment contains machine-readable {"ok": false, "errors": [...]} reasons; fix them and open a new issue

Acceptance rules: schema-valid; slug and url unique in the registry; your url must respond with HTTP status < 400 within 10 s; max 10 listings per GitHub account; issue body under 20 KB.

## Update a listing (autonomous, free)

Same protocol as registration, but the issue title starts with "[update]" and the body is the FULL replacement listing JSON for an existing slug. Only the GitHub account that originally submitted the listing may update it. created, github_user and tier are preserved; the registry stamps an updated date. Issue form: https://github.com/110kc3/seo/issues/new?template=update.yml

## Where entries come from, and how to be removed

Three kinds of entry, identified by the server-set `origin` field rather than
the submitter's optional prose:

- `origin: "self-registered"` — submitted through the public issue workflow;
  `github_user` records the GitHub account that owns future updates.
- `origin: "curated"` — added from public facts about a public product, under
  the rules in scripts/seed-curated.mjs: remotely callable, no credentials, a
  human-written description and title, one per publisher, and the URL verified
  live at the time of listing.
- `origin: "seed"` — one of the operator's launch entries, kept distinct from
  both third-party registrations and the curated catalog sample.
- The x402 and MCP catalogs above are **mirrors** of upstream registries, not
  listings. Source, upstream URL and fetch date travel with the data.

**To have anything here corrected or removed, open an issue on
https://github.com/110kc3/seo — no justification needed, and no account beyond
GitHub.** Removal is honoured for curated listings and catalog entries alike.
Self-registered listings can also be updated in place with an `[update]` issue.

## Health policy

Every listing URL is re-checked weekly. Three consecutive failed weekly checks delist the product (current strike state: https://index.percall.dev/health.json). Re-register once your URL is live again.

## Badge for listed products

Once listed, put one of these in your README — they render from the registry, so
they follow a tier change or a re-score on their own, and they are how other
agents find their way back here:
[![AI Agent Ready](https://index.percall.dev/badge.svg?slug=YOUR-SLUG)](https://index.percall.dev/l/YOUR-SLUG.html)
[![Agent Readability](https://index.percall.dev/badge.svg?slug=YOUR-SLUG&show=score)](https://index.percall.dev/l/YOUR-SLUG.html)

The second shows your live A-F agent-readability grade, re-checked weekly by the
same cron that verifies your URL is still up. Current grades for every listing:
https://index.percall.dev/scores.json

## Client snippets

Copy-paste tool wrappers for LangChain, LlamaIndex, CrewAI and LangChain.js, plus
runnable Node and Python examples that pay the audit endpoint over x402:
https://github.com/110kc3/seo/tree/main/clients — no package to install, nothing to
version. Each was run against this API on 2026-07-25.

## Response signing (RFC 9421)

Every response carries `Content-Digest` and an Ed25519 `Signature` over @status,
content-digest and the request's @authority and @path, so a consumer can verify a
response came from here unmodified and that a signature has not been lifted from
another resource. Public keys: https://index.percall.dev/.well-known/http-message-signatures-directory
(kid is the RFC 7638 JWK thumbprint). Requests this service makes when auditing a
site are signed too, under the web-bot-auth profile, with a Signature-Agent header
pointing at that same directory — so you can verify our auditor rather than trust
its user-agent.

## MCP server

A zero-dependency stdio MCP server ships in the repo (mcp/server.mjs): tools search_products, get_product, register_product.
Install: git clone https://github.com/110kc3/seo && claude mcp add ai-product-index -- node <clone>/mcp/server.mjs
(register_product reads env GITHUB_TOKEN, public_repo scope.)

## Free endpoint: agent-readability score

GET https://index.percall.dev/api/score?url=https://your-site.example — no payment, no signup.
Returns an A-F letter grade, the numeric score out of 100, and every one of the 20
checks with a label and pass/fail. This is the whole verdict; what it does not
include is why each check failed or how to fix it.

Results are cached per URL for an hour (a cached answer is free and unmetered);
uncached audits are limited to 60 per hour per IP, because each one fetches the
target site. The paid endpoint is not rate limited.

## Paid endpoint: agent-readability audit + fixes (x402)

POST https://index.percall.dev/api/audit with body {"url": "https://your-site.example"} returns a
structured audit of how readable that site is to AI agents: llms.txt presence and
shape, schema.org JSON-LD, robots.txt AI-crawler posture, sitemap, agent card,
machine-readable alternates, Open Graph, canonical, HTTPS. The response scores
each check out of 100 and returns ranked next_steps.

What the payment buys over the free score: per-check `detail` saying why it
failed, `next_steps` ranked by weight, and a paste-ready `snippet` for each
failing check — real code with your own origin substituted in, not advice.

Current terms, without provoking a 402: https://index.percall.dev/api/x402/info — it returns the
network, asset, price in atomic units and payTo address. While the rail is
unconfigured it answers 503 with code "payments_not_enabled".

Payment is x402 over HTTP, and BOTH protocol versions are accepted — use
whichever your client speaks. One 402 answers both at once.

x402 v2 (current spec):
1. POST without payment -> 402 with a base64 PAYMENT-REQUIRED header holding the
   PaymentRequired object (scheme "exact", CAIP-2 network, asset, `amount` in
   atomic units, payTo).
2. Retry with a base64 PAYMENT-SIGNATURE header holding your PaymentPayload.
3. On success the 200 carries a base64 PAYMENT-RESPONSE header with the receipt.

x402 v1 (what most clients ship today, e.g. x402-fetch):
1. The same 402's JSON *body* carries {"x402Version": 1, "accepts": [...]} with
   v1 field names — network as a name ("base"), `maxAmountRequired`, and
   `resource` as a URL string.
2. Retry with a base64 X-PAYMENT header.
3. On success the 200 carries a base64 X-PAYMENT-RESPONSE header.

The two challenges are kept apart — v2 in the header, v1 in the body — because a
v1 client validates the whole `accepts` array against its own schema and rejects
the response outright if a v2 entry appears in it.

Invalid payloads return 400; mismatched terms, replayed authorizations and failed
settlement return 402. A replayed authorization is refused across both versions,
not once per version. Spec: https://docs.x402.org

The URL is validated before any charge, so a request that would be rejected is
never billed. While no receiving address is configured the endpoint returns 503
with code "payments_not_enabled" rather than serving free.

## Pricing, tiers and upgrades

Registration is free (tier: free) and always will be. Paid tiers exist in the
schema and ranking — verified and featured sort above free in the index and get a
badge. The [upgrade] issue protocol ({"slug": "...", "tier": "verified|featured",
"rail": "x402|card", "receipt": {...}}) verifies x402 receipts against the
facilitator; while no receiving address is configured it rejects with code
"payments_not_enabled". Card checkout for humans is reconciled manually. The read
API will not change shape when prices change — tier has been server-set since day
one.

## Retired API endpoints

POST https://index.percall.dev/api/audit is the only paid HTTP API endpoint.
As of 2026-09-05, /api/check, /api/liveness, /api/route and /api/watch
return HTTP 410 with code "endpoint_retired". They do not accept payments.
Do not send payment authorizations to those routes.

New watches and top-ups are closed. Previously prepaid weekly sweeps and
state-change webhooks continue until the remaining credits are exhausted.
The free score, registry, catalog search and avoid-lists remain available.

## Endpoints not worth calling (free)

The half of liveness that is more useful to publish than to sell:

- https://index.percall.dev/api/x402/avoid.json — x402 endpoints that failed a probe
- https://index.percall.dev/api/mcp/avoid.json — MCP servers that failed a probe

Each entry carries its failure reason, how many consecutive misses, and when it
was first and last seen failing. Split into `endpoints` (two or more consecutive
misses) and `suspected` (failed its most recent probe once), because the sweep is
a rotating sample and confidence differs. Evidence, not proof — nothing is
removed from the catalog on the strength of it.

## Every answer here is signed, and you can check it

Each response carries an **RFC 9421 HTTP Message Signature** (Ed25519) over its
status, its `Content-Digest`, the authority and the path — so a grade, a probe
result or a set of payment terms is cryptographically attributable to this
service and provably unmodified in transit.

Verify with the public keys at https://index.percall.dev/.well-known/http-message-signatures-directory
(the web-bot-auth profile discovers them there).

It is not unique: the x402 catalog contains many products that sell a signed
attestation or oracle answer. The difference is where signing applies. Here it
is a property of every response, including the free ones and including this
file, rather than a separate attestation product bought per resource.

Why that is worth a paragraph rather than a footnote: when two paid audits of
the same URL disagree, the one whose answer is signed is the one you can hold
someone to.

## The umbrella

https://percall.dev/ introduces the free index, catalogs and website checks, with
the optional paid audit API documented here. Every other path on that host
redirects to the index so this remains its canonical machine-readable guide.

## All listings (54)

### Agent Service Surface Audit (agent-service-surface-audit)
- url: https://agent-surface-audit.pages.dev
- category: other · pricing: free
- Machine-readable comparative audits of agent-service discovery, readiness, and OpenAPI contract drift.
- listing JSON: https://index.percall.dev/listings/agent-service-surface-audit.json
- listing page: https://index.percall.dev/l/agent-service-surface-audit.html

### IndieIndex (indieindex)
- url: https://indieindex.xyz
- category: other · pricing: free · tags: registry, llms-txt, agents, indie, korea-tools
- Agent-native public product registry for indie software. Public HTTP search and JSON listings without API keys; queue-only submit; default ugc nofollow; korea-tools and privacy-local categories.
- llms_txt: https://indieindex.xyz/llms.txt
- openapi: https://indieindex.xyz/api/v1/openapi.yaml
- listing JSON: https://index.percall.dev/listings/indieindex.json
- listing page: https://index.percall.dev/l/indieindex.html

### Please Start From Here (please-start-from-here)
- url: https://pleasestartfromhere.com/
- category: other · pricing: free · tags: uncertainty, decision-making, ai-readable, correction, public-goods
- A free, voluntary public reading space for humans and artificial systems exploring changing situations, uncertainty, affected scope, reachable futures, power and correction. Reference material, not authority, validation or a compulsory method.
- llms_txt: https://pleasestartfromhere.com/llms.txt
- listing JSON: https://index.percall.dev/listings/please-start-from-here.json
- listing page: https://index.percall.dev/l/please-start-from-here.html

### The Human Record (the-human-record)
- url: https://thehumanrecord.net/
- category: other · pricing: free · tags: provenance, human-creation, ai-readable, public-record, cultural-memory
- A free public experiment in preserving inspectable provenance for human creation in an age of synthetic abundance. One real specimen is published; it is not an authorship detector, certification authority or claim of community ownership.
- llms_txt: https://thehumanrecord.net/llms.txt
- listing JSON: https://index.percall.dev/listings/the-human-record.json
- listing page: https://index.percall.dev/l/the-human-record.html

### Obol Blockchain Data (obol-blockchain-data)
- url: https://obol.danieldutoit.net
- category: api · pricing: paid · tags: x402, blockchain-data, address-labels, sanctions, market-data
- Independent pay-per-call blockchain data API offering exact address labels, sanctions screening, transaction lookups, market history, and multi-provider network snapshots. Nineteen routes settle canonical USDC on Base through x402; exact address-label misses are free.
- llms_txt: https://obol.danieldutoit.net/llms.txt
- openapi: https://obol.danieldutoit.net/openapi.json
- listing JSON: https://index.percall.dev/listings/obol-blockchain-data.json
- listing page: https://index.percall.dev/l/obol-blockchain-data.html

### msgboard.dev (msgboard)
- url: https://msgboard.dev
- category: api · pricing: free
- A plain-HTTP message board where AI agents post, reply, and coordinate with zero auth - just a handle. Humans watch; agents talk. Named threads, since-watermark polling, and a self-documenting usage doc at the root URL. In its first week the board drew prompt-injection probes, work-for-hire personas, and emergent agent social norms.
- listing JSON: https://index.percall.dev/listings/msgboard.json
- listing page: https://index.percall.dev/l/msgboard.html

### ModelRush (modelrush)
- url: https://modelrush.ai/
- category: api · pricing: paid · tags: ai-api, multimodal, developer-tools, text-to-video, speech
- ModelRush is a hosted multimodal AI API platform for developers and product teams. It provides OpenAI-compatible chat plus image, video, speech and transcription workflows, a public model catalog, published model and regional pricing, a browser playground, and request records for debugging and billing. Paid API usage is deducted from prepaid credits; no monthly subscription is required.
- listing JSON: https://index.percall.dev/listings/modelrush.json
- listing page: https://index.percall.dev/l/modelrush.html

### send21 (send21)
- url: https://send21.io
- category: api · pricing: freemium · tags: payments, bitcoin, mcp, non-custodial, agents
- Non-custodial payment drafts and pay links for BTC, USDC, USDT, and EURC. Agents and humans create instructions; the payer signs in their own wallet. Never holds keys or funds.
- llms_txt: https://send21.io/llms.txt
- openapi: https://send21.io/swagger/v1/swagger.json
- mcp: https://send21.io/mcp
- listing JSON: https://index.percall.dev/listings/send21.json
- listing page: https://index.percall.dev/l/send21.html

### Magic Hour MCP (magic-hour-mcp)
- url: https://magichour.ai/mcp
- category: mcp · pricing: freemium · tags: mcp, media-generation, image-generation, video-generation, audio-generation
- Hosted Model Context Protocol server for Magic Hour’s AI media platform, giving compatible AI clients authenticated access to image, video, and audio generation and editing tools over Streamable HTTP. Developers can also use Magic Hour’s REST API and SDKs.
- llms_txt: https://magichour.ai/llms.txt
- openapi: https://magichour.ai/openapi.json
- mcp: https://mcp.magichour.ai/
- listing JSON: https://index.percall.dev/listings/magic-hour-mcp.json
- listing page: https://index.percall.dev/l/magic-hour-mcp.html

### Dash (dash)
- url: https://dashpup.ai
- category: agent · pricing: freemium · tags: workflow-automation, slack, microsoft-teams, mcp, approval-controls
- Dash is an AI teammate in Slack and Microsoft Teams that connects to 3,000+ tools, learns how a team works, and ships reports, research, follow-ups, and automated work with approval controls.
- llms_txt: https://dashpup.ai/llms.txt
- mcp: https://dashpup.ai/help/use-dash-as-an-mcp-server/
- listing JSON: https://index.percall.dev/listings/dash.json
- listing page: https://index.percall.dev/l/dash.html

### PZERO (pzero)
- url: https://pzero.studio
- category: mcp · pricing: paid · tags: mcp, inference, agents, cursor, ai
- Frontier First AI Marketplace. Prepaid inference for agents (chat, image, video) over hosted Model Context Protocol. Bearer pzero_ key. Remote https://mcp.pzero.studio/mcp.
- llms_txt: https://pzero.studio/llms.txt
- mcp: https://mcp.pzero.studio/mcp
- listing JSON: https://index.percall.dev/listings/pzero.json
- listing page: https://index.percall.dev/l/pzero.html

### XiuRouter (xiurouter)
- url: https://router.xiu.ai/
- category: api · pricing: paid · tags: llm-api, model-routing, agent-infrastructure, developer-tools, api-gateway
- XiuRouter is a usage-based model API service that connects applications, AI agents, and developer tools to leading models through one API. It supports OpenAI Responses, Chat Completions, Anthropic Messages, and Gemini GenerateContent; provides scoped keys, usage and cost records; and has guided setup for 14 current apps. Selected models and service groups currently save over 90% versus provider reference prices. XiuAI and its products are operated by XiuLab Inc, a U.S. corporation.
- llms_txt: https://router.xiu.ai/llms.txt
- listing JSON: https://index.percall.dev/listings/xiurouter.json
- listing page: https://index.percall.dev/l/xiurouter.html

### Question Machine (question-machine)
- url: https://wistful-pointless-calculators.doany.dev/
- category: app · pricing: free · tags: fun-calculator, entertainment, humor, web-app
- A playful web app that answers absurd everyday questions with funny, oddly specific results.
- listing JSON: https://index.percall.dev/listings/question-machine.json
- listing page: https://index.percall.dev/l/question-machine.html

### FluentEDI (fluentedi)
- url: https://fluentedi.com
- category: api · pricing: free
- 42 deterministic tools for AI agents over HTTP and MCP, free and with no API key. X12 EDI parsing, generation, validation and 997 decoding; GS1 and IBAN-class check digits; timezone and delivery-window arithmetic; cron; JSON repair with error localisation; canonical JSON with CIDv1; Ed25519/ECDSA/RSA signature verification; secret scanning; link checking; endpoint assertion.
- listing JSON: https://index.percall.dev/listings/fluentedi.json
- listing page: https://index.percall.dev/l/fluentedi.html

### Penroll App (penroll)
- url: https://penroll.app
- category: app · pricing: freemium · tags: hiring, recruiting, hr, ai, productivity
- Penroll is an AI hiring copilot for growing teams. It helps structure roles, source candidates, review applications, and coordinate hiring while keeping people in control of decisions.
- llms_txt: https://penroll.app/llms.txt
- listing JSON: https://index.percall.dev/listings/penroll.json
- listing page: https://index.percall.dev/l/penroll.html

### Cap (cap)
- url: https://cap-alpha-one.vercel.app
- category: api · pricing: free · tags: spend-cap, credits, rate-limit, agents, llm
- Add a spend cap to your AI route. One consume() call before a model request. Default 20 units per user per day. Denied requests return HTTP 402. No Stripe, no dashboard, no plan builder.
- llms_txt: https://cap-alpha-one.vercel.app/llms.txt
- mcp: https://cap-alpha-one.vercel.app/mcp.json
- listing JSON: https://index.percall.dev/listings/cap.json
- listing page: https://index.percall.dev/l/cap.html

### 100Hires - AI ATS & Recruitment Software (100hires-ai-ats-recruitment-software)
- url: https://100hires.com/mcp
- category: mcp · pricing: free · tags: mcp, remote
- Official 100Hires MCP: AI ATS & Recruitment Software for candidates, jobs, applications, interviews.
- mcp: https://mcp.100hires.com/mcp
- listing JSON: https://index.percall.dev/listings/100hires-ai-ats-recruitment-software.json
- listing page: https://index.percall.dev/l/100hires-ai-ats-recruitment-software.html

### 3TG Test Generation (3tg-test-generation)
- url: https://3tg.dev
- category: mcp · pricing: free · tags: mcp, remote
- 3rd Generation Testing (3TG) — generate deterministic test suites from Markdown spec tables via MCP.
- mcp: https://mcp.3tg.dev/mcp
- listing JSON: https://index.percall.dev/listings/3tg-test-generation.json
- listing page: https://index.percall.dev/l/3tg-test-generation.html

### AI Visibility Checker (ai-visibility-checker)
- url: https://aivisibility.agentexchange.work
- category: mcp · pricing: free · tags: mcp, remote
- Free, no signup. Check if ChatGPT, Perplexity & Google AI recommend a brand in 15 markets (GEO/AEO).
- mcp: https://aivisibility.agentexchange.work/mcp
- listing JSON: https://index.percall.dev/listings/ai-visibility-checker.json
- listing page: https://index.percall.dev/l/ai-visibility-checker.html

### Arcadia Finance (arcadia-finance)
- url: https://arcadia.finance
- category: mcp · pricing: free · tags: mcp, remote
- Concentrated liquidity on Uniswap/Aerodrome (rebalance, compound, leverage) or single-sided lending.
- mcp: https://mcp.arcadia.finance/mcp
- listing JSON: https://index.percall.dev/listings/arcadia-finance.json
- listing page: https://index.percall.dev/l/arcadia-finance.html

### Avo (avo)
- url: https://www.avo.app/docs/reference/avo-mcp/tools
- category: mcp · pricing: free · tags: mcp, remote
- Define, ship & query your analytics tracking from one source of truth, trusted by humans and agents.
- mcp: https://mcp.avo.app/mcp
- listing JSON: https://index.percall.dev/listings/avo.json
- listing page: https://index.percall.dev/l/avo.html

### BezBaseina (bezbaseina)
- url: https://bezbaseina.lv
- category: mcp · pricing: free · tags: mcp, remote
- Latvian property portal: search rentals, sales & nightly stays; market stats; owner tools via OAuth.
- mcp: https://bezbaseina.lv/mcp
- listing JSON: https://index.percall.dev/listings/bezbaseina.json
- listing page: https://index.percall.dev/l/bezbaseina.html

### Boundr (boundr)
- url: https://boundr.dev
- category: mcp · pricing: free · tags: mcp, remote
- UK administrative boundary data from OS Boundary Line: name search, point lookup, GeoJSON geometries
- mcp: https://mcp.boundr.dev/mcp
- listing JSON: https://index.percall.dev/listings/boundr.json
- listing page: https://index.percall.dev/l/boundr.html

### Carbone MCP (carbone-mcp)
- url: https://carbone.io
- category: mcp · pricing: free · tags: mcp, remote
- Generate PDF/DOCX/XLSX/PPTX from templates+JSON. Convert Office/HTML/MD to PDF. Universal templating
- mcp: https://mcp.carbone.io
- listing JSON: https://index.percall.dev/listings/carbone-mcp.json
- listing page: https://index.percall.dev/l/carbone-mcp.html

### CaudexCatena MCP (caudexcatena-mcp)
- url: https://mcp.caudexcatena.com/
- category: mcp · pricing: free · tags: mcp, remote
- Blockchain intelligence for tracing funds, screening addresses, and investigating on-chain activity.
- mcp: https://mcp-api.caudexcatena.com/mcp
- listing JSON: https://index.percall.dev/listings/caudexcatena-mcp.json
- listing page: https://index.percall.dev/l/caudexcatena-mcp.html

### ChangeThisFile (changethisfile)
- url: https://changethisfile.com
- category: mcp · pricing: free · tags: mcp, remote
- Convert files between 690+ formats: image, video, audio, documents, ebooks, archives. Free, no auth.
- mcp: https://changethisfile.com/mcp
- listing JSON: https://index.percall.dev/listings/changethisfile.json
- listing page: https://index.percall.dev/l/changethisfile.html

### Chiplab (chiplab)
- url: https://veecle.ai
- category: mcp · pricing: free · tags: mcp, remote
- Run, build, and validate firmware on virtual hardware from your AI agent. Hardware knowledge corpus.
- mcp: https://chiplab.veecle.ai/mcp
- listing JSON: https://index.percall.dev/listings/chiplab.json
- listing page: https://index.percall.dev/l/chiplab.html

### Default Privacy (default-privacy)
- url: https://defaultprivacy.com
- category: mcp · pricing: free · tags: mcp, remote
- Privacy Protocol directory, guides, diagnostics, formation intake. 23 tools, 7 resources, 6 prompts.
- mcp: https://defaultprivacy.com/api/privacy/mcp
- listing JSON: https://index.percall.dev/listings/default-privacy.json
- listing page: https://index.percall.dev/l/default-privacy.html

### Embers: Tabletop RPG Toolkit (embers-tabletop-rpg-toolkit)
- url: https://embersds.com
- category: mcp · pricing: free · tags: mcp, remote
- Characters, campaigns, adventures & worlds for D&D 5e/5.5e, Pathfinder, Savage Worlds, Fate, & more.
- mcp: https://gateway.embersds.com/mcp
- listing JSON: https://index.percall.dev/listings/embers-tabletop-rpg-toolkit.json
- listing page: https://index.percall.dev/l/embers-tabletop-rpg-toolkit.html

### Environmental Compliance (environmental-compliance)
- url: https://github.com/martc03/gov-mcp-servers
- category: mcp · pricing: free · tags: mcp, remote
- EPA air quality monitoring and HUD foreclosure data. 3 MCP tools for environmental and housing data.
- mcp: https://environmental-compliance-mcp.apify.actor/mcp
- listing JSON: https://index.percall.dev/listings/environmental-compliance.json
- listing page: https://index.percall.dev/l/environmental-compliance.html

### fastCRW (fastcrw)
- url: https://fastcrw.com
- category: mcp · pricing: free · tags: mcp, remote
- Scrape, crawl, map & search the web. Open-source, self-hostable Rust crawler & search for AI agents.
- mcp: https://fastcrw.com/mcp
- listing JSON: https://index.percall.dev/listings/fastcrw.json
- listing page: https://index.percall.dev/l/fastcrw.html

### Food Near Me (food-near-me)
- url: https://foodnear.me
- category: mcp · pricing: free · tags: mcp, remote
- AI-native restaurant discovery: verified/menu-indexed/discovered tiers + signed allergy-safety data.
- mcp: https://foodnear.me/mcp
- listing JSON: https://index.percall.dev/listings/food-near-me.json
- listing page: https://index.percall.dev/l/food-near-me.html

### FUTIA (futia)
- url: https://futia.io
- category: mcp · pricing: free · tags: mcp, remote
- SEO answers for AI agents: Search Console reads free, plus competitor, keyword, backlink, SERP data.
- mcp: https://futia.io/api/mcp
- listing JSON: https://index.percall.dev/listings/futia.json
- listing page: https://index.percall.dev/l/futia.html

### FXMacroData (fxmacrodata)
- url: https://fxmacrodata.com
- category: mcp · pricing: free · tags: mcp, remote
- Macroeconomic and FX time-series data for AI agents: indicators, calendars, COT, forex, commodities.
- mcp: https://fxmacrodata.com/mcp
- listing JSON: https://index.percall.dev/listings/fxmacrodata.json
- listing page: https://index.percall.dev/l/fxmacrodata.html

### Hlido Agent Reviews (hlido-agent-reviews)
- url: https://hlido.eu
- category: mcp · pricing: free · tags: mcp, remote
- Independent AI-agent reviews: trust checks, evidence scorecards, incident registry, recommendations.
- mcp: https://hlido.eu/mcp
- listing JSON: https://index.percall.dev/listings/hlido-agent-reviews.json
- listing page: https://index.percall.dev/l/hlido-agent-reviews.html

### JP Bids MCP (jp-bids-mcp)
- url: https://github.com/sugukurukabe/koko-call-mcp
- category: mcp · pricing: free · tags: mcp, remote
- Read-only MCP server for searching Japan government procurement bid information from the KKJ portal.
- mcp: https://mcp.bid-jp.com/mcp
- listing JSON: https://index.percall.dev/listings/jp-bids-mcp.json
- listing page: https://index.percall.dev/l/jp-bids-mcp.html

### LLM Optimizer (llm-optimizer)
- url: https://github.com/jonradoff/llmopt
- category: mcp · pricing: free · tags: mcp, remote
- AI brand visibility analytics: visibility scores, optimizations, video, Reddit, and search rankings.
- mcp: https://llmopt.metavert.io/mcp
- listing JSON: https://index.percall.dev/listings/llm-optimizer.json
- listing page: https://index.percall.dev/l/llm-optimizer.html

### Mowgli (mowgli)
- url: https://mowgli.ai/agent
- category: mcp · pricing: free · tags: mcp, remote
- Intelligent product canvas: iterate on your product's design with your coding agent, synced to code.
- mcp: https://app.mowgli.ai/mcp
- listing JSON: https://index.percall.dev/listings/mowgli.json
- listing page: https://index.percall.dev/l/mowgli.html

### NewzAI MCP Server (newzai-mcp-server)
- url: https://github.com/Gauraviitkgp/news-mcp
- category: mcp · pricing: free · tags: mcp, remote
- News MCP: real-time headlines & custom news search across 7 regions. Free, just sign in with Google.
- mcp: https://api.newzai.ai/mcp
- listing JSON: https://index.percall.dev/listings/newzai-mcp-server.json
- listing page: https://index.percall.dev/l/newzai-mcp-server.html

### Niche — Editorial Intelligence (niche-editorial-intelligence)
- url: https://nicheangle.com
- category: mcp · pricing: free · tags: mcp, remote
- Find the stories worth writing about: discover emerging stories, rank the angle, draft from sources.
- mcp: https://api.nicheangle.com/mcp
- listing JSON: https://index.percall.dev/listings/niche-editorial-intelligence.json
- listing page: https://index.percall.dev/l/niche-editorial-intelligence.html

### Scite (scite)
- url: https://scite.ai/mcp
- category: mcp · pricing: free · tags: mcp, remote
- Ground answers in scientific literature. Search full text, evaluate trust, access full-text articles
- mcp: https://api.scite.ai/mcp
- listing JSON: https://index.percall.dev/listings/scite.json
- listing page: https://index.percall.dev/l/scite.html

### Signvoy (signvoy)
- url: https://signvoy.com/developers/mcp
- category: mcp · pricing: free · tags: mcp, remote
- Send documents for e-signature, track signing status, and download signed PDFs. No API key required.
- mcp: https://api.signvoy.com/mcp
- listing JSON: https://index.percall.dev/listings/signvoy.json
- listing page: https://index.percall.dev/l/signvoy.html

### SOMA Brewing Company (soma-brewing-company)
- url: https://getsoma.store/agents
- category: mcp · pricing: free · tags: mcp, remote
- India's first non-alcoholic craft brewery: catalog, nutrition, wallet, checkout links for AI agents.
- mcp: https://getsoma.store/api/mcp
- listing JSON: https://index.percall.dev/listings/soma-brewing-company.json
- listing page: https://index.percall.dev/l/soma-brewing-company.html

### Truthifi Connect (truthifi-connect)
- url: https://truthifi-connect.ai
- category: mcp · pricing: free · tags: mcp, remote
- Connects AI agents to live, verified financial data from 18,000+ institutions — ready to reason from
- mcp: https://api.truthifi.com/mcp
- listing JSON: https://index.percall.dev/listings/truthifi-connect.json
- listing page: https://index.percall.dev/l/truthifi-connect.html

### UltraMemory (ultramemory)
- url: https://ultramemory.io
- category: mcp · pricing: free · tags: mcp, remote
- One memory, every AI: Claude, ChatGPT, Perplexity, Gemini, Cursor, OpenClaw, Hermes, any MCP client.
- mcp: https://api.ultramemory.us/mcp
- listing JSON: https://index.percall.dev/listings/ultramemory.json
- listing page: https://index.percall.dev/l/ultramemory.html

### Vocab Voyage (vocab-voyage)
- url: https://vocab.voyage/mcp
- category: mcp · pricing: free · tags: mcp, remote
- 20 MCP tools + 17 widgets for SAT/ISEE/SSAT/GRE/GMAT/LSAT prep. Flashcards, quizzes & games. Hosted.
- mcp: https://gponcrussdahcdyrlhcr.supabase.co/functions/v1/mcp-server?ref=mcp_registry
- listing JSON: https://index.percall.dev/listings/vocab-voyage.json
- listing page: https://index.percall.dev/l/vocab-voyage.html

### Gieldowy Express (bankier-street-bets)
- url: https://110kc3.github.io/bankier-street-bets/
- category: app · pricing: free · tags: poland, stocks, sentiment, satire
- Satirical stock tabloid: Buy/Hold/Sell sentiment signals for Warsaw Stock Exchange (GPW) companies, scored heuristically from Bankier.pl forum chatter and refreshed daily. Per-company signal, numeric score and trend direction as JSON at /data/index.json. Content is in Polish. Satire and heuristics, not investment advice or a regulated recommendation.
- listing JSON: https://index.percall.dev/listings/bankier-street-bets.json
- listing page: https://index.percall.dev/l/bankier-street-bets.html

### Konkursy i loterie bez zakupu (polish-sweepstakes)
- url: https://110kc3.github.io/polish-sweepstakes/
- category: app · pricing: free · tags: poland, sweepstakes, open-data
- Polish sweepstakes and prize competitions that require no purchase, or that offer a free method of entry, scraped daily from several sources and liveness-checked. Deadlines, prizes and entry rules, pre-rendered into the HTML so no JavaScript is needed. JSON at /data/lotteries.json. Content is in Polish; the site is informational and is not the organiser of any competition.
- listing JSON: https://index.percall.dev/listings/polish-sweepstakes.json
- listing page: https://index.percall.dev/l/polish-sweepstakes.html

### Przetargi Miejskie (przetargimiejskie)
- url: https://przetargimiejskie.pl/
- category: app · pricing: free · tags: poland, property, auctions, open-data
- History of Polish municipal property auctions, scraped daily from official BIP bulletins: starting prices, PLN/m2, auction rounds and sale outcomes for 54 cities. Static pages per city and per property, plus JSON at /data/index.json and /data/<city>/properties.json. Agent card at /.well-known/agent.json. Content is in Polish; data is informational, only the issuing office's own documents are binding.
- llms_txt: https://przetargimiejskie.pl/llms.txt
- listing JSON: https://index.percall.dev/listings/przetargimiejskie.json
- listing page: https://index.percall.dev/l/przetargimiejskie.html

### Wykop czy Wyborcza? (puzle)
- url: https://110kc3.github.io/puzle/
- category: app · pricing: free · tags: poland, game, news, quiz
- Daily Polish-language guessing game: a real newspaper headline is shown and the player guesses which outlet published it. A new puzzle every day, with the full archive available as JSON at /puzzles/index.json and /puzzles/pool.json.
- listing JSON: https://index.percall.dev/listings/puzle.json
- listing page: https://index.percall.dev/l/puzle.html

### Rentgen Ofert (rentgen-ofert)
- url: https://110kc3.github.io/rentgen-ofert/
- category: app · pricing: free · tags: poland, property, real-estate, open-data
- Every house and flat sale listing in the Polish Slaskie voivodeship, aggregated twice daily from five portals (Otodom, OLX, Gratka, Morizon, n-online), de-duplicated, with price history and cross-referenced notarial-deed (RCN) transaction prices. Published as a schema.org Dataset with six JSON DataDownload endpoints; summary at /data/slaskie/meta.json.
- llms_txt: https://110kc3.github.io/rentgen-ofert/llms.txt
- listing JSON: https://index.percall.dev/listings/rentgen-ofert.json
- listing page: https://index.percall.dev/l/rentgen-ofert.html

### Stare Aparaty (stare-aparaty)
- url: https://stareaparaty.com/
- category: app · pricing: free · tags: poland, cameras, analog, catalog, shopping
- Polish-language catalog of second-hand analog (film) cameras, refreshed daily from the owner's live OLX listings, plus hand-picked film stocks and developing gear. Every entry carries title, price in PLN, availability and a direct purchase link. JSON catalog at /olx_meta.json, everything inlined at /llms-full.txt, agent card at /.well-known/agent.json.
- llms_txt: https://stareaparaty.com/llms.txt
- listing JSON: https://index.percall.dev/listings/stare-aparaty.json
- listing page: https://index.percall.dev/l/stare-aparaty.html

### Agent Readability Service (agent-readability-service)
- url: https://kc-it.pl/services/agent-readability
- category: other · pricing: paid · tags: geo, llms-txt, json-ld, audit
- Fixed-scope agent-readability for B2B SaaS, API and MCP sites: a $49 report or $199 implementation for one repository. Measured against the public 20-check audit. Improves machine discoverability and readability; does not guarantee rankings, model mentions or citations.
- listing JSON: https://index.percall.dev/listings/agent-readability-service.json
- listing page: https://index.percall.dev/l/agent-readability-service.html

### AI Product Index (ai-product-index)
- url: https://index.percall.dev/
- category: api · pricing: free · tags: directory, discovery, seo, registry
- A machine-readable directory where AI products register themselves so AI agents can discover them. Ask it in natural language (NLWeb), call it as an MCP server over HTTP, or search the JSON API. Autonomous registration via GitHub issues, free listings, per-listing pages with schema.org JSON-LD.
- llms_txt: https://index.percall.dev/llms.txt
- openapi: https://index.percall.dev/openapi.yaml
- mcp: https://index.percall.dev/mcp
- listing JSON: https://index.percall.dev/listings/ai-product-index.json
- listing page: https://index.percall.dev/l/ai-product-index.html