fetch_source

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full behavioral burden. It discloses that output is formatted as 'clean numbered paragraphs + citation metadata' and explains paging behavior via start_paragraph. This is meaningful context beyond the schema, though it stops short of covering error or access behaviors.

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?

Three sentences, each earning its place: the core purpose and output format, pagination guidance, and a directive about cut_card quote fidelity. The most important information is front-loaded and there is no filler.

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?

The tool is simple and the description covers the core behaviors, input modes, and pagination. An output schema exists, so return-value details are not required. The only notable gap is the lack of guidance on relationship to sibling source-finding tools, but the description remains sufficient for correct invocation.

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 description coverage is 0%, so the description must compensate for the bare parameter names. It does so fully: url_or_id is explained as either an article/PDF URL or a fetched-source id, and start_paragraph is explained as the pagination continuation mechanism. Both parameters are semantically clear.

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?

The description clearly identifies the verb ('Fetch') and resource ('article/PDF' or a previously fetched source by id), and describes the output as numbered paragraphs plus citation metadata. It does not explicitly differentiate from sibling tools like find_sources, so it falls just short of a 5.

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?

The description gives clear operational context: fetching a source, re-opening a fetched source, and paging long sources. However, it does not explicitly state when to prefer this tool over sibling tools such as find_sources or search_cards, nor does it provide exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.