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

Beyond the single destructiveHint=false annotation, it discloses the auth requirement, optimistic-locking/409 conflict behavior, that null clears a field, that times must be ISO converted to Shanghai time, and a strong content policy (write only user-stated facts, never fabricate time/venue/guests/org/phone). That is substantial context the annotations do not 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?

Every clause carries information — login, set semantics, workflow, anti-fabrication, conflict handling — and the precondition is front-loaded. The semicolon-chained delivery is dense and slightly run-on, but no sentence is wasted.

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 3-parameter mutation with a nested free-form object, no output schema, and minimal annotations, the description covers auth, workflow, conflict recovery, and safety rules well. It only gestures at the response shape by referencing a 'missing' field without explaining it, which is the one remaining gap.

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, but the description adds real semantics the schema lacks: 'set' keys are activity/letter field paths, a null value clears the field, and time values are ISO strings normalized to Shanghai time. It does not enumerate valid field-path names, which remain discoverable only via get_activity_draft.

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 plus title make clear this edits an existing activity draft via a field-path patch, and it names the related siblings get_activity_draft and publish_activity_draft in the workflow. It does not explicitly distinguish itself from update_activity (the published-activity editor), leaving some ambiguity for an agent choosing between the two.

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?

It gives an explicit ordered workflow: read version with get_activity_draft, apply the update, and call publish_activity_draft only when 'missing' is empty. It also names a failure path (409 from another device → re-read, user edits win) and states a precondition (login required).

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