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

Annotations only say openWorldHint=true and destructiveHint=false; the description adds the material behaviors an agent needs — the booking is real and charged, the courier search starts right away, and pickup_at is capped at 4 days (30 for corporate). It also flags the safe test path via sandbox, which is exactly the kind of operational consequence annotations don't convey.

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?

One tight paragraph, front-loaded with the highest-stakes fact (real, charged delivery), then prerequisites and constraints in descending order of importance. No filler sentences.

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 multi-param nested write tool with no output schema, it covers cost, dispatch timing, scheduling limits, prerequisites and test mode. It doesn't say what comes back (job id, status) or how to undo a bad booking via stuart_cancel_job, which an agent would want given there is no output schema.

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. The description still adds value by tying pickup_at to a concrete scheduling window and by restating the 1-8 dropoff bound as a business constraint rather than just a maxItems. It doesn't explain assignment_code or the dropoff window fields, so it isn't a full 5.

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?

Opens with a specific verb+resource (creates a job) and immediately scopes it: one pickup, 1-8 dropoffs, real charge, dispatches a courier. That is clearly separable from stuart_validate_job, stuart_estimate_price and stuart_update_job without opening any 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?

Gives an explicit ordering of prerequisites (quote via stuart_estimate_price, check via stuart_validate_job, confirm with the user), names the sandbox for tests, and explains when the job dispatches immediately versus when pickup_at defers it. Both the when-to-use and the when-to-check-first conditions are present.

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