Comments: add comment to transaction or receipt

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

The description complements annotations by stating 'Not idempotent — calling twice may create duplicates', which is consistent with idempotentHint=false. It also indicates a write operation (readOnlyHint=false, destructiveHint=false). No contradictions; it adds useful duplication warning beyond the 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 relatively short and front-loaded with the purpose after a brief generic note. Each sentence serves a purpose: write warning, core function, parameter constraint. The generic WRITE note could be considered redundant if common across tools, but overall it is concise.

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?

Given 4 parameters fully described in schema and no output schema, the description covers the key constraint. However, it lacks information on return values, error behavior, or expected response after adding a comment. While the tool is simple, an agent might benefit from knowing what to expect post-call.

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?

While the input schema describes all 4 parameters (100% coverage), the description adds critical constraint: 'You have to submit either a transaction_id_by_customer or a receipt_id_by_customer.' This mutual exclusivity is not evident from individual parameter descriptions, adding significant value.

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 explicitly states 'add comment to transaction or receipt', providing a specific verb and resource. The note about needing either transaction_id_by_customer or receipt_id_by_customer further clarifies the scope. This clearly distinguishes it from sibling tools like accounts_add or receipts_add.

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 includes a clear note about the requirement to submit either a transaction_id_by_customer or a receipt_id_by_customer, providing necessary context for when to use this tool. However, it does not explicitly mention when not to use it or compare to alternatives, but the constraint is sufficient for an agent to decide.

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