update_credential

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

With no annotations provided, the description carries the full behavioral burden. It discloses non-obvious behavior: fields are merged by key, removeFields deletes fields, endpoints are replaced wholesale, and env:VAR indirection is supported. This goes beyond the schema and warns about destructive/replacement semantics.

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?

Two sentences with the purpose front-loaded and the key behavioral rules compactly listed. There is no filler or redundant restating of schema fields.

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 10-parameter mutation tool with no output schema and no annotations, the description covers core update semantics but omits behavior for several parameters and does not explain what happens to unspecified fields. It is useful but not fully complete for every calling scenario.

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 20%, so the description must compensate. It adds valuable semantics for the most nuanced parameters: fields (merge), removeFields (delete), endpoints (replace), and env:VAR references. However, it leaves tags, system, newName, authType, ttlSeconds, and description to self-explanatory names or the schema enum, so compensation is only partial.

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 opens with '更新已有凭据' (update existing credential), naming a specific verb and resource, and the 'existing' qualifier distinguishes it from add_credential and delete_credential. It also states concrete update behaviors (merge, remove, replace), so an agent can clearly identify this tool's role among 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?

The description clearly establishes that this tool is for modifying an existing credential, which tells an agent when to select it over add_credential or delete_credential. It does not explicitly name alternatives or list when-not-to-use conditions, but the context is unambiguous.

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