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

Annotations already declare write, non-idempotent, and non-destructive behavior. The description adds meaningful context beyond that: it pins obligations to their version and integrity hash at signing time, and clarifies the subscription requirement and header precedence for api_key. This enriches the agent's understanding of side effects and dependencies.

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 compact paragraphs that front-load the purpose and distinguish the tool from run receipts. It includes the key behavioral note (pinning) and a practical usage hint (api_key header). It is efficient, with minimal fluff, though a slight trim could make it even tighter.

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?

With 9 parameters and no output schema, the description covers the core purpose, the mapping behavior, the evidence type, and a prerequisite. It does not detail return values (no output schema expected) but provides enough for an agent to decide when to call and what to provide. Minor gaps such as error handling are not essential here.

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%, so the schema already documents every parameter, including api_key header precedence. The description does not add new semantic details about parameters beyond what the schema provides; it only reiterates the subscription requirement. Baseline 3 is appropriate when the schema fully covers parameter meaning.

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 specific verb 'Sign' and a clear resource: 'tamper-evident record of one of YOUR OWN controls or policies and the Bidda obligation nodes it maps to.' It also contrasts with 'run receipts' to clarify the design-side evidence role, effectively differentiating from other attestation-like sibling tools.

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?

It states when to use this tool: 'design-side evidence' vs 'running-side evidence' from run receipts, giving a clear context. It also states a prerequisite ('Requires an active Bidda subscription: pass api_key'). It does not explicitly name an alternative sibling tool, but the run-receipt contrast conveys appropriate usage.

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