opencode_auth_set

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

Annotations already indicate destructiveHint=true and readOnlyHint=false, so the agent knows this is a write operation. The description adds the useful context that credentials are stored globally and shared across all projects, which goes beyond the annotations. It does not disclose that existing credentials will be overwritten, but the destructiveHint partially covers that. Overall, the description adds moderate value without contradicting the annotations.

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 two sentences with no wasted words. The primary action is stated first, and the global-scope side effect is added efficiently. It is well-structured and front-loaded.

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 100% schema coverage, output schema, and annotations covering destructive behavior, the description is largely sufficient. It explains the tool's purpose and a key side effect (global storage). It could mention that existing credentials for the provider may be overwritten, but the destructiveHint already signals this. No critical information needed to invoke the tool correctly is missing.

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 100%—each parameter (key, type, providerId) has a description. The tool description adds no additional meaning beyond the schema, such as examples of valid provider IDs or auth types. Since the schema does the heavy lifting, the baseline of 3 is appropriate.

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 uses a specific verb ('Set') and resource ('authentication credentials for a provider') with a concrete example ('API key'). It is clear what the tool does, and the name opencode_auth_set reinforces this. However, it does not explicitly differentiate itself from sibling auth-related tools like opencode_provider_auth_methods or opencode_provider_oauth_authorize, so it lacks the sibling distinction that would merit a 5.

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 provides no guidance on when to use this tool versus alternatives. It does not mention that OAuth flows should use opencode_provider_oauth_authorize, nor does it state any exclusions or prerequisites. The only context given is that credentials are stored globally, which does not help an agent choose this tool over other auth-related operations.

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