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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent mutation. The description adds useful behavior beyond that: the name is immutable, and a kind that conflicts with existing statements is refused. It does not cover auth or response behavior, but it meaningfully extends the annotation profile.

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 compact and front-loads the update scope before rules and effects. The final sentence, 'Effects: account details updated,' is somewhat redundant, but overall there is little wasted text.

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 mutation tool with no output schema and basic annotations, the description provides enough context: what fields change, what cannot change, when the operation is appropriate, and that invalid kind/statement combinations are refused. It could say more about the required account_id or return behavior, but it is largely complete for invocation.

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 only 33%, so the description carries substantial weight. It maps five of the six parameters to plain-language fields (kind, institution, last four digits, opening date, notes) and adds the semantic constraint that name/account_id is not updatable. It still does not spell out optionality or formats beyond what the schema supplies.

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 states a specific verb and resource: changing what the register says about an existing account. It enumerates exactly which fields can change and explicitly notes that the account name is immutable, making it clearly distinct from add/close/account-listing siblings.

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?

It gives a clear context for use: corrections sourced from the person or a statement. It also implies an exclusion by stating that the name cannot be changed because statements are filed under it. It does not explicitly name sibling alternatives, but the use case is well framed.

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