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

Annotations already declare readOnly, idempotent and non-destructive, so the safety profile is covered. The description adds genuinely new context: it returns a digest and is explicitly not a password-hashing or key-derivation service, which clarifies capability boundaries beyond 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?

Front-loads the core action and stays compact, but the password caution is repeated three times ('do not hash passwords here', 'directly for password storage', 'not a password-hashing...service'), which is mildly redundant.

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 two-parameter read-only generator with no output schema, the description covers purpose, safety boundaries and return type adequately. Nothing essential is missing, though the return format is only named, not detailed.

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% and the algo enum with default is fully documented in the schema. The description echoes the algorithms but adds little syntax or format detail beyond the schema, so the baseline 3 applies.

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?

States a specific verb (compute) and resource (SHA-256 or legacy MD5 hash of text), and the title confirms the digest scope. It also carves itself away from sibling tools by explicitly ruling out password hashing, which routes to generate-password or is-password-safe.

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?

Gives explicit when-to-use ('non-secret fixture digests or to compare public text content') and when-not ('do not hash passwords here', 'do not use the legacy MD5 choice for security'). The routing to alternatives is unambiguous.

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