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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent write, so the safety profile is covered. The description adds that a plan_id is returned, which is useful since there is no output schema, but it does not say whether repeated logging creates duplicate plans or what happens on an invalid key.

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?

One sentence plus a compact JSON example, front-loaded with the action and ending with the return value. Nothing is wasted, though the example key is truncated ('fbk_…') so it cannot be copied verbatim.

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 5-parameter mutation tool with no output schema, the description covers the return value and shows a valid call shape, which is adequate. It leaves out required-vs-optional framing and the relationship to log_task_outcome, both of which matter for correct selection in this crowded sibling set.

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%, so the baseline applies: every parameter is already documented in the schema. The example adds a little value by showing a realistic plan string and confidence value, but it does not clarify the semantics of optional fields like task or steps beyond what the schema states.

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 ('Log your plan') plus the data captured and the return value (plan_id), which an agent can map to a concrete action. It does not, however, distinguish itself from the closely named sibling log_task_outcome, so the boundary remains implicit.

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?

The description gives no when-to-use or when-not-to-use guidance, and never mentions the obvious alternatives (log_task_outcome, report_outcome, start_work_session). The example implies a pre-execution logging moment, but the agent must infer that.

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