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

Annotations only flag destructiveHint/idempotentHint; the description adds substantive behavior beyond them: optimistic-concurrency semantics (stale version refused rather than overwritten), the effect of writing a new trip version rather than mutating in place, and the refusal list for unsupported edit types. This is exactly the extra context annotations cannot 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?

Front-loads the action and its scope, then prerequisites, then exclusions, then effects. The parenthetical about website-parity edits is dense but carries real selection value; no sentence is 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?

For a 4-parameter mutation tool with nested objects, no output schema and only partial schema coverage, the description supplies everything an agent needs: precondition, refusal conditions, out-of-scope cases, and the write effect. Nothing material is missing.

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 50%, with expected_version having no schema description; the description compensates by explaining that it must be the version last read via anywayr_get_trip and that mismatches are refused. It also constrains the valid contents of `changes`, though it doesn't restate the nested party/date sub-field semantics (which the schema covers).

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 (changes) plus the exact resource and editable fields (dates, number of travelers) on a trip, and explicitly rules out what it is not (no share/invite/book, no budget/title/preference edits). An agent can distinguish it from siblings like anywayr_get_trip or anywayr_plan_trip 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 the precondition (requires the version last read via anywayr_get_trip), the failure mode (stale version refused), and the out-of-scope cases routed elsewhere (multi-city date changes and child-leg party changes require the Anywayr website). Explicit when/when-not guidance.

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