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

Beyond the readOnlyHint and idempotentHint annotations, the description discloses pagination behavior (one page, nextCursor with same status filter), coverage (running, failed, completed including expired files), billing (no captioning charge), and a caution about user confirmation. It adds substantial behavioral context beyond what annotations alone provide, and does not contradict them.

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?

Every sentence earns its place: purpose, pagination, inclusion criteria, cost, alternative tool, safety warning, retry guidance. The most important information is front-loaded, and the description is tight with no filler.

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?

Given that an output schema exists (which likely covers return structure) and annotations cover the read-only/idempotent nature, the description provides all necessary operational details: ordering, pagination, inclusivity, cost, safety, and alternative routing. An agent can call this tool correctly without needing further clarification.

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 all three parameters have descriptions. The description adds value by explaining the cursor's dependency on the status filter ('pass nextCursor with the same status filter to continue') and the implicit ordering (newest first), which is not in the schema. It doesn't elaborate on the limit param, but the schema already covers that, so the baseline 3 is elevated to 4 due to the cursor/status nuance.

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 states a specific verb+resource: 'List your caption jobs newest first' with clear purposes (recover a lost job ID, review recent results). It also distinguishes itself from the sibling get_caption_job by explicitly saying to use that tool for single-job details and downloads.

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 when-to-use guidance (recover lost ID, review results) and names the alternative (get_caption_job) with a clear condition. It adds a safety warning about resubmission, telling agents that a missing row does not imply safe resubmission, and advises retrying with the original idempotencyKey. This goes beyond basic usage.

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