user_record_activity

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

With no annotations, the description carries the full burden and does well: it discloses the automatic last_active_at update and the return shape {recorded, activity_id}. It omits failure modes and permission/validation behavior, keeping it from a 5.

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 core action and side effect in the first line, then uses compact Args/Returns structure with no wasted prose. The Args section partly restates the schema, which is a minor redundancy.

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?

Covers purpose, trigger context, all parameters, and a return summary, which is sufficient given no annotations, no output schema, and a simple 3-param shape. Only failure/error behavior is left unaddressed.

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 0%, so the description must compensate, and it does: all three params are documented, including example values for activity_type (thought/decision/reminder/...), the 500-char cap on detail, and the 'local' default for user_id. The activity_type examples are not declared as an enforced enum, leaving some ambiguity about allowed values.

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?

Uses a specific verb+resource ('记录一次用户活跃事件') and discloses the side effect (auto-updates last_active_at). This clearly separates it from read-only siblings like user_get_activity_stats and user_get_retention, though it never names a sibling explicitly.

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?

States the trigger context ('供其他工具/Agent 在关键行为后调用') and the downstream purpose (retention/activity stats), giving an agent a clear condition for calling it. No explicit when-not or named alternative is given, so it falls 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.