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

Annotations already indicate a non-readonly, non-idempotent write, and the description's 'Write a line' is consistent with that. It adds the useful detail that the line id is returned, but it does not disclose side effects, append-only behavior, or whether duplicates are created on repeated calls. No contradiction with annotations.

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?

The description is a single sentence that front-loads the core behavior, includes the relevant record types, and mentions the return value. Every element earns its place with no filler or repetition of the tool name.

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 simple three-parameter tool with an output schema, the description conveys the core purpose and return value. However, it leaves the required fields under-specified and provides no guidance about valid values for 'kind' or what 'reference_id' should reference, so the agent is not fully equipped to invoke 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 description coverage is 0%, so the description must compensate, but it only partially does. It implies that 'kind' relates to gate decisions, order intents, or handoffs, yet it never maps those to the parameter, and it gives no meaning or format for 'reference_id' or the optional 'note'.

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 uses a specific verb ('Write') and resource ('audit record'), and clarifies the scope by naming the three record types: gate decision, order intent, and handoff. It is clear enough, but it does not explicitly differentiate itself from the sibling action tools such as create_order_intent or gate_transaction.

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 implies when to use the tool by listing the three event types it logs, but it never states explicit conditions, exclusions, or alternatives. An agent must infer that this is for audit logging rather than for performing the underlying gate/order/handoff actions.

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