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

Annotations already declare readOnly, idempotent, and non-destructive, so the description's addition of 'does not execute JavaScript or bypass access controls' and cache-related behavior ('Keep fresh=false to allow cache reuse') exceeds the annotation baseline. This gives the agent useful constraints beyond the structured fields.

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 three short sentences, each earning its place: the first defines the action, the second sets boundary conditions, the third explains parameter usage. No filler or redundancy.

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 2 parameters, full schema documentation, and an output schema present, the description sufficiently covers purpose, constraints, and parameter behavior. It does not need to explain return values because the output schema exists, and it gives enough context to distinguish this from sibling URL tools.

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 already describes both 'url' and 'fresh' in detail. The description restates these constraints rather than adding new meaning, though it subtly reinforces the 'public' and 'new upstream fetch' concepts. Baseline 3 is appropriate when the schema carries the burden.

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 opens with 'Extract bounded citation and reference links with visible labels,' which is a specific verb-resource pairing that clearly differentiates this tool from siblings like web.url.links or web.url.extract. The qualifiers 'bounded' and 'with visible labels' add distinctive scope.

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?

It provides clear operational context: 'Use only for public HTTP(S) resources' and 'does not execute JavaScript or bypass access controls,' plus explicit guidance on the fresh parameter. However, it does not name alternative tools or state when not to use this tool, stopping short of a full 5.

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