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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds two things annotations cannot: the per-call credit cost and the fact that the response includes a freshly generated UUID. The UUID detail arguably sits in tension with idempotentHint=true since output varies per call, but that is an output-determinism nuance rather than a claim of side effects, so it does not rise to a contradiction.

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 compact clauses with zero waste; the operation is front-loaded and the cost disclosure is parenthetically separated so it does not obscure the core purpose.

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, no-output-schema utility, the description covers purpose, cost, and the shape of the returned value (hash plus UUID), which is exactly the information an agent cannot get from the input schema. The only gap is the absence of any default or guidance for the optional 'algorithm' parameter.

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 both 'text' and 'algorithm' including the SHA variant list. The description only implies that a text input exists and adds nothing about algorithm selection or defaults, which is the correct baseline when the schema does the heavy lifting.

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 names a specific verb and resource ('SHA hash of text') and additionally discloses a non-obvious output component ('plus a fresh UUID'). It is unambiguous about what the tool does, though it never mentions a sibling tool or contrasts itself with utilities like text_stats.

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?

There is no guidance on when to use this versus alternatives, no preconditions, and no exclusions. The only supplementary information is a cost note, which is pricing rather than usage direction.

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