update_transaction_details

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

The description adds valuable behavioral context beyond the annotations: 'Omitted fields stay unchanged; null clears a field' explains partial update semantics, and 'Codex must request user approval' is a critical operational constraint. This goes beyond the destructiveHint and readOnlyHint flags.

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 two sentences long, with the first stating the core purpose and the second adding essential behavioral rules. No unnecessary words or repetition.

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 update tool with three parameters and no output schema, the description fully covers what is updated, how omitted/null values behave, and the approval requirement. It is complete enough for an agent to invoke correctly without further clarification.

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 67%, and the description compensates by explaining that omitted fields are left unchanged while null clears them—this is not explicit in the schema. It also clarifies the 'payee/payer' field meaning. The transaction_id semantics are left to the schema, which is acceptable.

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 ('Update') and resource ('one existing ZenMoney transaction'), and explicitly names the fields affected ('payee/payer and/or comment'). This clearly distinguishes it from sibling tools like change_transaction_category or delete_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 provides clear context on what the tool does (updates payee/comment of one transaction), making it easy to infer when to use it. However, it does not explicitly mention alternatives or exclusions, though the sibling tool list helps. The approval requirement is also stated.

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