reference_excerpt

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

With no annotations, the description carries the full burden of disclosing behavior. It adds important traits such as 'SSRF-guarded and capped' and explains the query-centered behavior ('around query if given, otherwise the head'), which goes beyond the schema. While it doesn't cover error handling or exact output limits, it provides meaningful context for safety and output characteristics.

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?

The description is remarkably concise, using two sentences to convey the action, the query behavior, safety/limits, and intended use. Every clause earns its place, and there is no redundant or filler content.

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 relatively simple (3 parameters, no output schema, no annotations). The description covers purpose, behavior, and usage adequately, mentioning output type ('plain-text excerpt') and constraints ('capped'). It lacks some granularity (e.g., exact excerpt length or error cases) but is sufficient for straightforward 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 descriptions cover 2 of 3 parameters (query and radius) with reasonable detail, and the description adds behavior around the query parameter ('around query') and implies safety for URL handling ('SSRF-guarded'). The URL parameter lacks a schema description, but the description's safety note partially compensates. Since coverage is moderate (67%), this is a baseline 3 with slight extra value.

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 states the tool's function: fetching a page and returning a focused plain-text excerpt. It specifies the verb ('fetch'), the resource ('page'), and the output ('excerpt'), and the closing phrase 'For reading a specific passage' distinguishes it from sibling tools like reference_inspect and reference_read_source.

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 conveys a clear use case: 'For reading a specific passage,' and indicates the excerpt will center around a query or fall back to the head. However, it does not explicitly state when not to use this tool or name alternatives, so it stops short of a 5.

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