fill_vault_item

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

With no annotations, the description carries the full burden. It usefully discloses the return profile ('only true or an error without secret text') and the negative guarantee ('never returns a snapshot'), but says nothing about permissions, preconditions (field must be visible/focused), or failure modes beyond 'an error'.

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?

Three short sentences, front-loaded with the core action, with no filler. Minor formatting noise (double backticks) but the content is tight and 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?

The tool mutates page state with zero annotations and 0% parameter documentation. The description covers output shape (partly redundant with the existing output schema) but leaves parameter meaning, auth needs, and preconditions unexplained, so it is not complete enough for a 4-param write action.

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 0% across 4 parameters (index, item_id, provider, field_kind). The description only vaguely gestures at 'provider' and explains none of index, item_id, or field_kind, so it fails to compensate for the undocumented schema.

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 ('Fill a visible field from a vault item') and clarifies the item is resolved by the registered provider. It does not explicitly distinguish itself from the close siblings fill_secret or type_text, so an agent must infer the boundary.

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?

No when-to-use guidance and no alternatives named. Given siblings like fill_secret and type_text, the description should say when to prefer this tool over those, but it offers nothing beyond an implied 'fill a field' context.

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