fetch_docRetrieve full live content of a doc URL from a registered llms.txt source, after locating it via search_docs.
Fetch full content of a doc url. The url must be under the llms.txt directory of a registered source, or listed by a source already searched (use search_docs first). Content is fetched live.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | Document URL from a search_docs result |
Changes observed during successful MCP inspections.
v1.0.0Input schema / $schemaPrevious value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"Input schema / additionalPropertiesRemoved value: -falsev0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered; the description adds that 'content is fetched live,' telling the agent results are not cached/stale snapshots. It doesn't describe failure modes or whether unreachable URLs raise or return empty, so it is solid but not exhaustive.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences, front-loaded with the core action and followed by the URL constraint; no filler. The second sentence packs two conditions together, which is dense but still readable and earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a single-parameter read tool with annotations covering the safety profile and no output schema, the description supplies the key operational constraint (valid URL origins) and the live-fetch behavior. Return-shape detail is not required, though error handling for out-of-scope URLs is unaddressed.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% (baseline 3), and the description goes beyond the schema's 'Document URL from a search_docs result' by adding the alternative valid source (llms.txt directory of a registered source). That extra constraint meaningfully narrows what URLs are acceptable.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb and resource ('Fetch full content of a doc url') and immediately scopes it to URLs from the llms.txt directory or a prior search_docs result, which cleanly separates it from the sibling search_docs. An agent can identify the operation without opening the schema.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly names the prerequisite flow ('use search_docs first') and the two valid URL origins, which is real routing guidance. It stops short of stating when NOT to use it (e.g., for non-URL lookups) or what happens if the URL is invalid/out of scope beyond the implicit failure.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.