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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior. The description adds useful behavioral context beyond that: it searches multiple surfaces in one call, routes calculator-shaped questions toward Labs, and tells the agent that results will name the next tool to call.

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 dense sentences, each earning its place: the first defines scope, the second gives explicit usage timing, and the third explains result routing. No filler or repetition of schema details.

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 multi-surface search tool with four parameters, an output schema, and rich annotations, the description covers scope, usage timing, and post-invocation routing. It could be slightly more explicit about which simpler sibling to use for plain core-knowledge queries, but that gap is minor given the 'rather than only a core knowledge unit' phrasing.

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 100%, so every parameter is already documented in the schema. The description adds only general context about surfaces and Labs routing, not parameter-level syntax or constraints, so the baseline of 3 is appropriate.

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 names a specific verb ('Search') and a precise resource set — core corpus, first-party essays, executable Labs, epistemic claims, and the Homeric Atlas — and positions it as an all-surfaces entry point. It also distinguishes it from narrower single-surface tools by noting it is for questions that may need calculation, essay, or claim-audit results.

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 explicit conditions for when to use this tool first: questions that may require calculation, a long-form essay, or a claim audit rather than only a core knowledge unit. It does not explicitly name sibling alternatives for the non-target cases, so it stops short of full when-not/alternative guidance.

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