fill_secret

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It usefully reveals that the tool never accepts or returns the secret value and that fills are constrained by provider, origin, field kind, expiry, and use limit. However, it does not disclose side effects, behavior on expired/mismatched capabilities, or any other runtime effects beyond the act of filling.

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 three sentences with no filler. The first sentence delivers the core function, and the following sentences provide meaningful constraint and secrecy information. Every sentence 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?

Given the tool has three parameters, 0% schema coverage, and no annotations, the description is not complete enough for an agent to invoke it reliably. The output schema exists, so return values need not be explained, but the missing definitions of 'index' and 'include_snapshot', plus the lack of failure/edge-case behavior, leave significant gaps.

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%, so the description must compensate for the bare parameter schema. It adds meaning for the capability object by explaining that it names a provider and an opaque handle, but it says nothing about 'index' or 'include_snapshot'. Since two of three parameters remain effectively undocumented, the description only partially compensates.

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 clearly states a specific action and object: 'Fill a field from an opaque secret capability.' It also communicates the key distinguishing trait — the secret value is never accepted or returned — which differentiates it from sibling tools like type_text. This is not a tautology; it tells an agent what the tool actually does.

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?

The description implies when to use the tool by explaining that the capability is bound to exact origins, a field kind, an expiry, and a use limit. However, it never explicitly says when to prefer fill_secret over alternatives such as type_text or click, and it gives no exclusions. Usage context is present but left largely to inference.

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