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

Annotations already cover idempotency and non-destructiveness. The description adds meaningful behavioral context by mentioning that computation happens through a 'receipted external execution' and that the digest is reproducible, giving insight beyond the structured 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 short and front-loaded with the core action. However, phrases like 'receipted external execution' and 'stable machine endpoint' are jargon-heavy and add limited clarity for the space they occupy.

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 four required parameters, a nested object, zero schema descriptions, and no usage guidance, the description is not complete enough for an agent to invoke this tool correctly. The output schema helps with return values, but the meaning of required inputs remains underspecified.

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 0%, so the description must compensate for all four required parameters. It addresses only 'data' and 'encoding' indirectly by mentioning UTF-8 or base64 bytes, while 'consumer_id' and especially the nested 'invocation_context' object are left completely unexplained.

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 and resource: 'Compute a SHA-256 digest' for customer-supplied bytes, and clarifies the supported encodings. This clearly distinguishes it from sibling tools like evidence_verify and schema_validate, which serve different functions.

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?

No guidance is given on when to use this tool versus alternatives, nor are any exclusions or preconditions mentioned. The phrase 'stable machine endpoint' hints at a use context, but it does not help an agent decide between hash_compute and its siblings.

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