Borrowing it
Nothing to install: this file belongs to synchronicity-labs/mcp-server. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/synchronicity-labs/mcp-server/main/AGENTS.mdgit clone --depth 1 https://github.com/synchronicity-labs/mcp-serverWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/synchronicity-labs/mcp-server/agents-md)<a href="https://agentmods.dev/instructions/synchronicity-labs/mcp-server/agents-md"><img src="https://agentmods.dev/badge/instructions/synchronicity-labs/mcp-server/agents-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/synchronicity-labs/mcp-server/agents-md"><img src="https://agentmods.dev/badge/instructions/synchronicity-labs/mcp-server/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.01944 | $0.01944 |
| Opus 5.5 | $0.00778 | $0.00778 |
| Sonnet 5.5 | $0.00389 | $0.00389 |
| Haiku 4.5 | $0.00194 | $0.00194 |
Grade A, and why
mcp-server AGENTS.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured today.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 94 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md
Guide for coding agents working in this repository. CLAUDE.md links here.
What this is
sync.'s MCP server. It runs two ways from the same code:
- Hosted at
https://mcp.sync.so/mcp: Streamable HTTP, OAuth proxied toapi.sync.so, one Porter replica. ChatGPT, Claude.ai, Claude Code, Cursor and Codex connect here. - stdio through
npx @sync.so/mcp-serverwithSYNC_API_KEY, for local clients.
Every merge to main deploys production. Treat each merge as a release.
A merge that changes version in package.json also publishes that version to npm
(.github/workflows/publish.yml); merges that keep the version only deploy.
server.json is the MCP Registry listing.
Its version must equal package.json's, and a merge that changes it publishes the
listing (.github/workflows/publish-mcp-registry.yml). The registry never replaces a
published version, so bump both versions in any PR that edits server.json.
Where things live
| Path | Owns |
|---|---|
src/server.ts |
Tool assembly, HOSTED_HTTP_TOOL_ALLOWLIST, per-profile visibility (isAppOnlyTool), instructions (INSTRUCTION_PARTS), tools/list descriptors |
src/client-profile.ts |
Maps the handshake client name to a presentation profile (chatgpt, codex, claude, generic). Presentation only, never permissions |
src/tools/ |
Hand-written tools; generator.ts turns public OpenAPI operations into generated tools |
src/openapi/ |
Fetches and parses api.sync.so/api-json at startup |
src/http-server.ts, src/http-session.ts, src/session-registry.ts |
Express app, OAuth proxy routes, /mcp, /health, request-scoped MCP sessions |
src/rate-limits.ts |
Request limits per verified user and OAuth client, plus per-address limits on rejected credentials |
src/auth/ |
OAuth proxy provider (SDK server-legacy), bearer verification, device auth for stdio |
src/chatgpt-app.ts, deploy/chatgpt/ |
Immutable ChatGPT UI releases built from sync-api-v2 apps/chatgpt; see docs/chatgpt-release.md |
chatgpt-plugin/ |
ChatGPT and Codex plugin package: manifest, listing copy, and skills.source.json, the pinned commit of synchronicity-labs/skills it packages skills from; see docs/chatgpt-plugin.md |
server.json |
MCP Registry listing: name, description, remote URL; scripts/check-server-json.mjs keeps it publishable |
glama.json |
GitHub users who can claim and edit the Glama listing |
scripts/ |
Memory and session suites, UI packaging, monitor, post-deploy smoke check, pre-commit size check |
docs/ |
Maintainer notes (docs/maintainers.md), release, availability and auth details |
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- today Changed · +11 lines · +308 tokens per session 6f8176915b74
- 3d ago Changed · +2 lines · +106 tokens per session b71283606224
- 6d ago First seen · 81 lines · 1,530 tokens per session scan A a261439d4f69
mcp-server AGENTS.md is an instructions file published in the GitHub repository synchronicity-labs/mcp-server (1 stars, last pushed yesterday), licensed MIT. It adds 1,944 tokens to every session, about $0.0078 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-31.
mcp-server AGENTS.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| mcp-server AGENTS.mdsynchronicity-labs/mcp-server | Instructions file | 1 | yesterday | MIT | A | 1,944 | Codex, OpenCode |
| vscode buildNext.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 9,719 | GitHub Copilot |
| next.js AGENTS.mdvercel/next.js | Instructions file | 143k | yesterday | MIT | A | 7,461 | Codex, OpenCode |
| langchain AGENTS.mdlangchain-ai/langchain | Instructions file | 149k | yesterday | MIT | A | 4,680 | Codex, OpenCode |
| vscode oss-third-party-notices.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 5,516 | GitHub Copilot |
| vscode copilot-instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 3,093 | GitHub Copilot |
| deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness | Instructions file | 274k | 2d ago | MIT | A | 4,313 | Codex, OpenCode |