MCP.Market

Postcept MCP server

by Postcept·io.github.Postcept/mcp·v0.3.3·1 stars
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Verify agent actions against the system of record and get signed completion receipts.

B77/100grade B
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Safety scan
B77/100

full report

Adoption
New

1 stars37 downloads/wk

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If you have run it, two minutes of your experience saves the next person an afternoon.

Postcept tools (6, 1 write)

write = sends, deletes, buys or posts

Read from the package source without running it. The installed server may list more.

  • get_verification

    Fetch a past verification (and its signed receipt) by id, e.g. to re-read the result

  • reconcile_verification

    Re-run a past verification against the live system of record (continuous reconciliation).

  • verified_completion_rate

    Read the organization's Verified Completion Rate: the share of claimed completions that

  • verify_cancellation

    Verify that a subscription the agent claims to have cancelled is actually cancelled in

  • verify_refundwrite action

    Verify that a refund the agent claims to have issued actually completed in the system

  • verify_ticket

    Verify that a support ticket the agent claims to have resolved is in the expected state

Public scan report

scanner v0.1.9 · 2026-09-25 · same rubric, same numbers if you re-run it

no findings
  • Code scan5 source files scanned25/25
  • –Live reliabilityno gateway calls yet and no remote to proben/a
  • –Tool poisoningtools not inspected (local package is not executed); not countedn/a
  • Auth qualitystatic API keys via environment variables6/15
  • Maintenancelast push 56 days ago12/15
  • Maintainer identityregistry namespace matches repository owner7/10
Overall 77/100. Components that don't apply are left out of the denominator. Any critical finding is an F.RubricAppeal a findingJSON

How Postcept compares

Against every graded AI and agents MCP server, from our own scans and uptime checks. Updated after each scan run.

Safety score
77/100
higher than 50% of 4,460 AI and agents servers
Tools
6
the typical AI and agents server has 6
Tools that change things
17%
typical: 0%. Fewer write tools means less an agent can break
GitHub stars
1
more than 50% of 2,711 AI and agents servers
Downloads a week
37
more than 28% of 1,538 AI and agents servers with a package

What its tools let an agent do: 5 read · 1 change

Install Postcept in Claude Code, Cursor or VS Code

Runs npx -y @postcept/mcp on your machine. Read the scan report first; the gateway never runs local packages.

claude mcp add mcp -- npx -y @postcept/mcp
Add to Cursor

What the publisher says

From the Postcept repository's README, as published. We do not edit it. Read it on GitHub

@postcept/mcp

A Model Context Protocol server that exposes Postcept, outcome verification for AI agents, as MCP tools.

After an agent performs a high-risk action (a refund, a subscription cancellation, a support-ticket resolution), it calls a verify_* tool to confirm the action actually completed in the system of record (Stripe, Zendesk, and more) and obtain a signed completion receipt. "done" becomes proof, not a claim.

The server is a thin wrapper over the live Postcept HTTP API. It holds no credentials of its own beyond your Postcept API key, and verification is read-only against your systems of record.

Configuration

Create an API key in the Postcept dashboard under API keys.

Use with Claude Desktop / Claude Code

{
  "mcpServers": {
    "postcept": {
      "command": "npx",
      "args": ["-y", "@postcept/mcp"],
      "env": { "POSTCEPT_API_KEY": "pcpt_sk_..." }
    }
  }
}

Tools

Every verify_* tool accepts test: true to run against the deterministic sandbox connector (excluded from your Verified Completion Rate), so an agent can exercise the full flow without a live system of record.

A non-verified result (incomplete, duplicated, mismatched, policyfailed) means the work is not** done. Surface the gap and recover.

Advisory, by design

MCP puts the verification call in the agent's hands, which makes it the right integration for development, demos, and workflows where the agent's judgment is already trusted. It is advisory: an agent can skip the call, pass the wrong identifiers, or ignore the answer.

For consequential actions, enforce the decision outside the agent. The workflow or orchestrator calls the Postcept API (or the SDK's guard()) itself and branches on safetoclaim_complete before anything customer-facing happens. The agent then receives the allowed outcome instead of deciding it. Both patterns use the same API and the same receipts, what changes is who owns the branch.

Development

pnpm --filter @postcept/mcp build       # compile to dist/
pnpm --filter @postcept/mcp typecheck
POSTCEPT_API_KEY=pcpt_sk_... node dist/index.js   # stdio server

Nothing above is checked by us. What we check is on the safety report.

Postcept: common questions

Is Postcept MCP server safe?
Mostly: it is graded B (77/100). Read the Postcept safety report
How do I install Postcept?
It runs on your machine. Copy the Claude Code, Cursor, VS Code or Claude Desktop config from the install section.
Does Postcept need an API key?
Yes. The registry entry asks for POSTCEPT_API_KEY.
Is Postcept maintained?
The last commit was 95 days ago (2026-08-01). The latest release is v0.3.3.
What can I use instead of Postcept?
Servers from other publishers that do the same job: Emilia Protocol MCP server, three.ws Provenance MCP server and Mockserver MCP server.
How does Postcept compare with other AI and agents MCP servers?
safety score 77/100 (higher than 50% of 4,460 AI and agents servers); tools 6 (the typical AI and agents server has 6); tools that change things 17% (typical: 0%. Fewer write tools means less an agent can break). Full comparison.

Alternatives to Postcept

Same job from other publishers: the closest match first, then the best rated.

  • Emilia Protocol
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  • three.ws Provenance
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    More from nirholas →
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  • Mockserver
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  • Decionis
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