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

Goes well beyond the annotations: discloses login requirement, that scope can be auto-downgraded to TEMP for expired needs, the recorded=false failure signal, and—critically—the 20-entry cap with oldest-entry eviction. This capacity/eviction behavior is non-obvious and not derivable from readOnly/destructive hints.

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-loaded with the login gate and tightly packed with semicolon-separated clauses; almost every clause carries actionable content. Slightly dense, but no meaningful 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 mutation tool with no output schema, the description covers auth, side effects (downgrade, eviction), and related operations. It is close to complete; only the exact response shape for recorded=false path is left implicit.

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 description coverage is 100% and already documents scope enums, needId downgrade behavior, and text normalization. The description mentions scopeDowngraded and same-entry scope updates, but this largely restates what the schema description already provides, so baseline 3 applies.

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+resource: record WANT/AVOID matching directions for icebreaker matching, matching the title. It clearly delineates from siblings by naming list_my_match_preferences, pause_need_icebreak, and revoke_my_match_preference as related-but-different operations.

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?

Explicit precondition ('先list_my_match_preferences') and explicit alternatives with their own roles ('pause_need_icebreak暂停单需求', 'revoke_my_match_preference撤销'). The '确认原意后' clause further frames when to invoke it. Routing to alternatives is unambiguous.

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