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

Goes well beyond the annotations: idempotency is stated ('giving the same values again changes nothing'), mutation semantics ('Overwrites the previous values'), a hard constraint ('Notes written by the user cannot be changed'), deletion being out of scope, and the auth requirement with explicit failure behavior. This is exactly the extra context annotations cannot carry.

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 first sentence front-loads the verb, resource, and kind→field mapping; subsequent short clauses cover idempotency, overwrite, the user-note restriction, the deletion sibling, and auth. No padding sentences.

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?

Covers identity of the tool, mutation behavior, idempotency, a notable constraint, deletion routing, and auth failure mode. With 19 parameters fully documented in the schema and an output schema present, nothing essential is missing.

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% and the schema already documents each parameter including kind-specific meanings. The description restates the kind→fields mapping but adds little syntax or format detail beyond what the schema provides, so the baseline 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?

Starts with a specific verb+resource ('Sets the state of an existing case file...') and then enumerates the four kinds it operates on, each with its editable attributes. This lets an agent distinguish it from create_account_item and delete_account_item without opening the schema.

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?

Explicitly names delete_account_item as the tool for deletion ('Nothing is deleted: deletion is delete_account_item'), which is a clean exclusion. It also states the OAuth requirement and that the tool reports missing accounts. It doesn't enumerate when to prefer get_account_item or create_account_item, so it falls short of full routing guidance.

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