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

With no annotations, the description carries the full burden and does well: it discloses the auth requirement ('Requires: token'), the one-shot nature, the lack of a current-password requirement on first use, and the 409 error on repeat invocation. It falls short of 5 because it cites a 'change-password' tool that does not appear in the sibling set, and it does not say whether setting a password affects the existing bearer token.

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?

Dense and front-loaded: the target account and the core purpose come first, followed by constraints and errors. The 409 condition is stated twice (mid-description and again as 'Typical error'), which is mild redundancy that costs a point.

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 one-parameter mutation with no output schema and no annotations, the description covers auth, error behavior, constraints, and the recovery rationale. Minor omissions remain around the fate of the existing token and the missing 'change-password' sibling, but nothing essential to invoking it correctly is absent.

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 0% and the single parameter has no description, so the description must compensate. It does so by adding a composition rule not present in the schema ('min 8 chars, letters+numbers') and by clarifying that no current password is needed. It could go further by stating format expectations (e.g. hashing, allowed character set), so 4 rather than 5.

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?

States a specific verb+resource ('Set a password for THIS account') and immediately scopes the target by credential ('the one your bearer token belongs to'). It is clearly distinguishable from sibling tools like login, reset_password, and register_account, which the description explicitly references.

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?

Gives explicit when-to-use ('Call this ONCE to enable email+password login as a recovery method'), when-not ('If a password was already set, this returns 409 (use change-password instead)'), and an alternative path. The agent does not need to infer the trigger condition.

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