Fetch a web page or spec by URL for reading. Returns the page content (HTML converted to Markdown; long pages are windowed — pass offset with the same url to keep reading, guided by totalLength/truncated), same-site pageLinks to explore the documentation further, and any OpenAPI/Swagger specLinks...
AI agents call fetch_api_doc to retrieve information from Zion without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
url | string | Yes | |
offset | number | — |
Parameters from the server's own tool schema.
This tool purely retrieves and reads API documentation and specifications from URLs. It has no side effects—it cannot modify, delete, execute, or perform financial operations. The pagination mechanism (offset, totalLength) and fetch budget (15 fetches per session) are read-only constraints. The mention of 'importing' a spec is guidance for the user, not a capability of this tool itself.
From the tool's definition Fetch a web page or spec by URL for reading. Returns the page content... Explore iteratively by fetching returned links. The tool only retrieves and returns documentation content with no mention of modification, deletion, or execution capabilities.
Risk signalsAccepts URL/endpoint input (url)
Attacks that exploit this kind of access
Fetch a web page or spec by URL for reading. Returns the page content (HTML converted to Markdown; long pages are windowed — pass offset with the same url to keep reading, guided by totalLength/truncated), same-site pageLinks to explore the documentation further, and any OpenAPI/Swagger specLinks found. Explore iteratively by fetching returned links, within a budget of 15 fetches per session (fetchesRemaining). Prefer importing a discovered spec via tpa import-from-openapi; otherwise author configs with the granular TPA schema ops. It is categorised as a Read tool in the Zion MCP Server, which means it retrieves data without modifying state.
fetch_api_doc accepts 2 parameters: url, offset. Required: url. The full parameter table on this page comes from the server's own tool schema.
Register the Zion MCP server in PolicyLayer and add a rule for fetch_api_doc: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Zion. Nothing to install.
fetch_api_doc is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the fetch_api_doc rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for fetch_api_doc. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
fetch_api_doc is provided by the Zion MCP server (zion-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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