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 bar is lower. The description still adds real behavioral context beyond them: it enumerates what the payload contains and discloses a business rule that 'no hit rate is shown until ten results exist' — a non-obvious threshold an agent would otherwise not know. It does not cover pagination or failure modes, but the added value is genuine.

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?

Two sentences, no padding, with the usage trigger front-loaded ahead of the payload description. The middle clause ('what happened with the primary source and the number, what it did to the Call') is a slightly loose list, but every sentence earns its place.

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 full burden of explaining returns, and it does list the salient fields plus the ten-results rule. But those fields are named in undefined jargon ('the Call', 'the number', 'primary source'), so an agent still cannot fully predict the shape or meaning of the response, and sibling differentiation is absent. Adequate, with clear gaps.

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?

The tool takes zero parameters (empty object schema, additionalProperties false), so per the rubric the baseline is 4. There is nothing for the description to disambiguate, and it correctly does not invent parameter semantics.

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 does state a resource and what comes back ('the tests that came in: verdict, what happened with the primary source and the number, what it did to the Call'), which is more than a restatement of the title. However, the core noun 'the Call' and 'the number' are undefined domain jargon, and nothing distinguishes this from siblings like deepstack_docket, deepstack_tape, or deepstack_story. An agent can guess it is a results/outcome read, but the purpose is only implied rather than cleanly stated.

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?

'Use when the user asks what resolved and how the Call fared' is an explicit trigger condition, which is better than nothing. But there are no exclusions and no routing to alternatives despite a dense sibling set (docket, tape, sides, story, search) that plausibly overlaps. Usage is implied by one fuzzy trigger phrase rather than clearly bounded.

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