Look up sources

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description needn't argue that. It adds useful content about the shape of returned records, but says nothing about what happens with out-of-range or nonexistent numbers, or whether results are ordered as requested.

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?

One compact sentence with no filler, and the identifying content (numbered sources, cited as [n]) is front-loaded. Minor cost: the trailing clause 'how that kind of source is read' is vague and slightly hard to parse.

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?

With no output schema, the description carries the burden of describing returns and does list the record fields, which is the right instinct. It leaves gaps for an agent with one required parameter: no error behavior for invalid numbers and no hint about result ordering or the 60-item cap.

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% and the single parameter is documented with an example ([164, 170]), so the baseline is 3. The description's '[n]' phrasing reinforces what the numbers mean but adds no format or bounds guidance beyond the schema.

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?

Identifies a specific resource (numbered citation sources) and enumerates what each record contains (title, links, kind, reading guidance), which sets it apart from generic siblings like get_entry or search_radar. It is phrased as a noun fragment rather than a verb+resource statement, so the 'look up' action comes mainly from the title.

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 '[n]' notation implicitly tells the agent these are the reference markers appearing in Radar text, so the usage context is inferable. It never states when to prefer this over get_entry or search_radar, nor what to do if a cited number is unknown.

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