UpdatePayee

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

Annotations already cover the mutation profile (readOnlyHint=false, destructiveHint=false, idempotentHint=true, openWorldHint=true), so the safety story is largely told. The description adds one genuinely useful non-obvious fact: the rename propagates to all of the payee's existing transactions. It does not mention permissions or error behavior, so it is moderate added value rather than rich.

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 short sentences with zero waste, and the core action is front-loaded before the side-effect note. Nothing could be cut without losing information.

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?

With an output schema present, return values need no explanation, and annotations cover the safety/idempotency profile. The description supplies the one behavioral fact an agent needs (transaction propagation) and the schema covers defaults, leaving only minor gaps such as permissions or failure modes.

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 payee_id, name, and plan_id (including the 'last-used' default and the ListPlans pointer) are fully documented in the schema itself. The description adds no parameter-level detail beyond that, so the baseline of 3 applies.

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 gives a specific verb+resource: 'Rename a payee.' This clearly separates it from sibling tools like Ynab_CreatePayee and Ynab_ListPayees by the distinct 'rename' verb. It stops short of explicitly naming or contrasting those siblings, so it is clear but not fully differentiated.

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?

There is no when-to-use guidance, no prerequisites, and no reference to alternatives (e.g., why rename via this tool rather than Ynab_UpdateTransactions). The agent is left to infer that this is the only path for renaming a payee.

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