update_transaction

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

Annotations already indicate idempotency (idempotentHint: true). Description adds useful constraint about split/group transactions but no further behavioral traits (e.g., response format, error behavior). Adequate but not exceptional.

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?

Two sentences, no fluff, front-loaded with the core action. Every word earns its place.

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 the tool's complexity (nested update object, high schema coverage but no output schema), the description covers the key constraint and API version change. Missing a note on return value, but output schema is absent, so minor gap.

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 description does not need to add much. It mentions 'writable fields' and the v2 envelope change, but does not explain individual parameters beyond what the schema provides. Baseline 3 is appropriate.

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 clearly states the verb (update) and resource (existing transaction), and distinguishes from siblings by explicitly mentioning that split or grouped transactions cannot be modified and should use corresponding tools.

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?

Provides direct when-to-use and when-not-to-use guidance: cannot modify split/grouped transactions, and directs to use split/group tools instead. No ambiguity.

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