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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety bar is largely met by structured fields. The description adds genuine domain context beyond them: result ordering (newest first), that ids are returned, and that no credits are consumed — the last being a meaningful cost guarantee for an agent operating under a budget. It does not mention pagination behavior or what happens when more than the limit exist.

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 filler. The resource and ordering are front-loaded, and the read-only/cost constraint plus the follow-up routing arrive before any need to consult the schema.

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 one-parameter, read-only listing tool with rich annotations and no output schema, the description covers purpose, ordering, returned ids, cost behavior, and next steps. The only real gap is what the list looks like when the account has more cases than the limit — an edge case an agent may hit but not one that blocks correct invocation.

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?

With schema description coverage at 100% and a single optional `limit` parameter documented with default and bounds, the schema carries the parameter burden fully. The description adds the ordering guarantee but says nothing about how limit interacts with truncation or total counts, so it adds only marginal meaning beyond the schema. Baseline 3 applies.

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 and resource ("List this account's cases"), defines the resource inline ("named groups of results"), and specifies ordering and returned identifier ("newest first, with their ids"). The inline definition of what a case is meaningfully separates it from list_analyses in the sibling set.

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?

Explicitly frames this as a lookup/discovery step whose output should be fed to get_case_summary or analyze_case_image, which tells the agent exactly when to call it. It also sets a negative boundary ("never runs an analysis and never spends credits"), routing analysis intent to analyze_case_image. It does not explicitly contrast with create_case or list_analyses, so it stops short of full alternative coverage.

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