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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds one genuinely non-obvious behavioral fact beyond them: hashing is irreversible, so secrets should not be submitted. It says nothing about the output format (hex string? length?), which matters for a hash utility with no output schema.

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?

Two short sentences, no filler, and the core purpose is front-loaded ahead of the caveat. Nothing could be removed without losing information.

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 utility with no output schema, the description covers purpose and adds a privacy caveat, which is reasonable. The missing default algorithm and unspecified return format (digest encoding/case) are real gaps an agent cannot resolve from structured fields alone.

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 carry the parameter burden, and it largely does not beyond echoing the enum values already in the schema. Most importantly it never states which algorithm is used when the optional `algorithm` argument is omitted, nor how the input text is encoded before hashing.

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?

"SHA hash of a text" states a specific verb (hash) and resource (text), and the parenthetical enumerates the supported algorithms, so the agent knows exactly what the tool computes. It does not, however, distinguish itself from the nearest sibling (encode_decode), which an agent might plausibly reach for instead.

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?

Usage is implied by the name and by the utility-tool neighborhood, and the privacy caveat functions as a partial "when not to use" signal. There is no explicit statement of when to prefer this over encode_decode or how to pick among the four algorithms.

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