set_message_importance

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

Substantially exceeds what annotations convey: stale revisions fail before a matching-value no-op, edits are metadata-only (no new inbox notice or repeated instruction), priority grants no authority, and identical retries replay ahead of activation/lifecycle/revision checks. The idempotentHint and destructiveHint annotations are corroborated and elaborated rather than merely restated.

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?

Four sentences, front-loaded with purpose, then preconditions, return values, and failure/activation semantics. Dense but every clause carries operative information about revisions, idempotency, or activation; no 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?

No output schema exists, yet the description enumerates the return fields (message_id, revision, importance, changed), covers the revision-conflict path, metadata-only effects, idempotent replay, and the server-activation requirement. An agent has everything needed to invoke and interpret it correctly.

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 genuine semantics: it identifies where expected_revision must come from (inbox, history or sender receipt) and states the ordering rule that a stale revision fails before a matching-value no-op can occur, which the schema does not express.

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 with explicit scope: 'Change only your message's low/normal/high/urgent priority.' The word 'only' plus the enumerated values make clear this targets the importance field alone, distinguishing it from sibling mutators like reply_message or acknowledge_message.

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 clear preconditions: requires a current expected_revision sourced from inbox, history or sender receipt, plus a nonempty idempotency_key, and notes the tool requires explicit server activation. It does not name an alternative tool or state when-not to use it, so it stops short of a 5.

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