Borrowing it
Nothing to install: this file belongs to alpacahq/alpaca-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/alpacahq/alpaca-mcp-server/main/AGENTS.mdgit clone --depth 1 https://github.com/alpacahq/alpaca-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/alpacahq/alpaca-mcp-server/agents-md)<a href="https://agentmods.dev/instructions/alpacahq/alpaca-mcp-server/agents-md"><img src="https://agentmods.dev/badge/instructions/alpacahq/alpaca-mcp-server/agents-md.svg" alt="Measured on agentmods" 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 | $0.01625 | $0.01625 |
| Opus 5 | $0.00813 | $0.00813 |
| Sonnet 5 | $0.00325 | $0.00325 |
| Haiku 4.5 | $0.00162 | $0.00162 |
Grade A, and why
alpaca-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 8d ago.
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.
Copies of this mod
2 near-identical copies found in the catalogue:
- alpaca-mcp-server-RFJq AGENTS.md — 100% identical, 0 lines differ
- alpacahq_alpaca-mcp-server AGENTS.md — 86% identical, 6 lines differ
How it starts
The opening of the file, as written. The whole thing — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent Instructions
Architecture Overview
This MCP server auto-generates tools from bundled OpenAPI specs (src/alpaca_mcp_server/specs/) using FastMCP's from_openapi(). Tool names, descriptions, and output risk classifications are defined in tool_registry.py. Complex endpoints (orders, historical data) use hand-written overrides in overrides.py and market_data_overrides.py. Toolset filtering is defined in toolsets.py. A trust-boundary middleware (security.py) wraps every tool result in a security envelope to mitigate prompt injection via tool outputs.
The test suite has three layers:
tests/test_integrity.py— Spec ↔ toolset ↔ names consistency (no network)tests/test_server_construction.py— Server builds correctly and exposes the expected tool set (no network)tests/test_paper_integration.py— Real API calls against Alpaca paper (needs credentials)
CI is defined in .github/workflows/ci.yml with two jobs: test-core (runs on every PR) and test-integration (runs when ALPACA_API_KEY / ALPACA_SECRET_KEY secrets are available).
Syncing OpenAPI Specs
When asked to "sync the MCP server" or "update specs", follow this process:
Step 1: Download latest specs
Run the sync script:
./scripts/sync-specs.sh
After downloading, the script rewrites the declared OpenAPI version from 3.1.2 to 3.1.1. FastMCP parses specs with openapi-pydantic, which only accepts 3.1.0 and 3.1.1 and rejects anything newer, so without this the server builds zero tools. Expect a one-character difference from the published spec. Remove that line once openapi-pydantic supports 3.1.2.
Step 2: Diff the specs
Check what changed:
git diff src/alpaca_mcp_server/specs/
Classify every change into one of three categories:
A. Modified existing endpoints
Parameter or schema changes to endpoints already in the allowlist (toolsets.py).
Action for auto-generated tools: No code changes needed — the spec update is sufficient.
Action for overrides: If the modified endpoint has its operationId in OVERRIDE_OPERATION_IDS (e.g., postOrder), the auto-generator is bypassed and the hand-written override in overrides.py or market_data_overrides.py is used instead. Spec changes do NOT flow through to overrides automatically. For every override whose underlying spec changed, you must:
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.
- 8d ago First seen · 121 lines · 1,625 tokens per session scan A 3f2917fc7ab4
alpaca-mcp-server AGENTS.md is an instructions file published in the GitHub repository alpacahq/alpaca-mcp-server (950 stars, last pushed 4d ago), licensed MIT. It adds 1,625 tokens to every session, about $0.0081 per session on Opus 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 2026-08-30.
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spec-kit AGENTS.md
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