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

Goes well beyond the annotations (which only declare not-read-only, open-world, not-destructive) by disclosing that a comment is mandatory, that the operation is reversible via resubmission, the return_to routing behavior, the per-call confirmation default, and the API-key access requirement. This is exactly the extra context annotations cannot carry.

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?

Front-loaded with the core action and mostly tight, though 'Sends a submitted report back to its submitter' overlaps with 'Rejects the whole report', and the trailing confirmation/auth sentences read as appended boilerplate.

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 mutation tool with no output schema and full parameter coverage, it covers outcome, reversibility, routing, confirmation, and auth. Lacking only explicit sibling routing, which leaves it just short of fully self-contained.

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 met by the schema alone, but the description adds the 'why' for comment (Expensify requires one) and clarifies return_to's role in multi-level workflows, slightly exceeding the schema's own wording.

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 ('Rejects the whole report') plus the mechanism ('sends a submitted report back to its submitter with a comment'). An agent can distinguish it from expensify_approve_report and expensify_submit_report 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?

Explains the outcome and follow-up path ('submitter can fix the report and resubmit') and when return_to matters on multi-level workflows, and gives confirmation guidance. It never explicitly excludes or names the alternative sibling (approve_report), so it stops short of full when/when-not routing.

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