check_credentials

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

No annotations provided, so description carries full burden. It adequately describes the three credential modes and what information is returned (availability status), but lacks explicit safety disclosure (read-only nature), rate limits, or side effects beyond the implicit non-destructive nature of 'Check' operations.

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 tightly constructed sentences with zero waste: action statement, explanatory detail of the three modes, and usage positioning. Information is front-loaded with the verb, and each sentence earns its place by conveying distinct information (what it does, what it shows, when to use it).

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 no output schema and the complexity of the three-mode credential system, the description successfully explains what the tool returns (availability across modes, BYO status). Minor gap: could briefly mention output format or example capability strings beyond the single 'email.send' example in the schema.

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 coverage is 100% (baseline 3), but description adds valuable context by explaining the 'three modes' framework that the optional capability parameter filters against. This enriches understanding of what the parameter controls within the broader credential ecosystem.

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 specific verb 'Check' with clear resource 'credential status across all three modes', distinguishing it from siblings like 'credential_ceremony' (which performs provisioning) and 'execute_capability' (which runs capabilities). It explicitly defines the scope (Rhumb-managed, ceremony guides, BYO) that differentiates this discovery tool from mere capability listing.

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 positions the tool with 'Start here to understand what you can execute', providing clear sequencing guidance for the credential workflow. While it doesn't explicitly name alternatives to avoid, the 'Start here' directive effectively establishes prerequisites for using sibling tools like 'execute_capability' or 'credential_ceremony'.

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