What if…

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

Annotations already establish readOnly/not-destructive/idempotent, so the safety profile is covered. The description adds genuine behavioral context beyond that: the session is not modified, and the response includes ranking, totals, margin, and whether the winner changes. It does not disclose output schema contents in detail, but the output schema exists and carries that burden.

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 sentences, zero filler, front-loaded with the core operation and the non-mutation guarantee. Every clause 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?

For a read-only hypothetical ranking tool with a rich schema and an output schema, the description covers purpose, safety, and return shape. The only minor gap is not naming which sibling to use instead for persisting changes, but overall it is complete enough to invoke correctly.

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%, so the baseline is 3, but the description adds meaning beyond the schema: it clarifies that both weights and score overrides are hypothetical and that omitting them falls back to stored values. It complements rather than repeats the parameter docs.

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?

States a specific verb (re-rank) and resource (options under hypothetical weights/scores), and immediately distinguishes itself from the mutation siblings by declaring it does not change the stored session. An agent can separate this from score_option or analyze without opening a schema.

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 concrete motivating questions ('what if we cared more about X?', 'what if that estimate is wrong?') that define when to reach for it, and the read-only, non-persisting framing implies when not to (use score_option to persist). It stops short of naming the alternative tools explicitly, so no exclusions are stated.

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