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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the mutation profile is covered. The description adds non-obvious cascade behavior beyond that: linked files move with the document, while a file also attached elsewhere is left in place and reported, plus the owned-trip restriction. It stops short of describing error/permission failure behavior, but adds real value over the annotations.

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?

Action and scope are front-loaded, followed by input sourcing, the unassign rule, ownership constraint, side effects, and return shape. Every sentence carries information; only the restated omit-trip_id rule slightly overlaps the schema description.

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 two-parameter mutation with no output schema, the definition covers target sourcing, the unassign path, ownership restriction, ambiguous-match handling, the file cascade side effect, and even the response contents (document, previous/new trip, count of re-pointed files). An agent has everything needed to call it safely.

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 baseline is 3, and both parameters are already documented in the schema. The description adds value by naming the source endpoints for each id (documents listing, trips_list) and restating the omit/null-to-library semantic as an operational instruction rather than a field note.

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 (move/assign) plus resource (travel document) and the two possible destinations (another owned trip or the general library). It is clearly distinguishable from siblings like audit_travel_documents or trip_update 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?

Explicitly says where to obtain inputs (document_id from a documents listing, trip_id from trips_list), when to omit trip_id (library), the ownership precondition, and to confirm when multiple documents could match. This is when/when-not/alternative routing in one place.

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