update_credentials

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

Given the absence of annotations, the description carries the full burden. It discloses that credentials are persisted to disk and take effect immediately, which is helpful. It could also mention potential side effects (e.g., invalidating active connections) or validation behavior, but the current detail is adequate for a simple update operation.

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 concise: one sentence for purpose, two for context, then a bulleted list of parameters. It is front-loaded with the most important information and every sentence adds value without redundancy.

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 simple two-parameter tool with an output schema (which covers return values), the description is complete: it covers what, when, how (persistence, no restart), and parameter semantics. No additional context is necessary for correct usage.

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?

With 0% schema description coverage, the description fully compensates by providing meaningful parameter explanations: a clear description of base_url with an example URL and a description of api_key noting it must be valid. This adds significant value beyond the schema's just titles and types.

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 begins with a clear verb-resource pair ('Update the Immich connection credentials') and provides specific use cases (API key rotation, server URL change). It is unambiguous and distinguishes itself from sibling tools, none of which deal with credentials.

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?

Explicitly states when to use the tool: when the API key is rotated or server URL changes. It also clarifies that no restart is required, aiding decision-making. No alternative tools exist for this purpose, so the guidance is complete.

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