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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower. The description still adds real value by asserting nothing is persisted and that the output is a stable, canonical hash suitable for citation. It does not disclose the canonicalization algorithm or the exact output format (hex length), which would be the last piece.

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?

One sentence with a parenthetical qualifier; every clause ('canonical', 'nothing stored', 'cite as evidence') carries distinct information and the core operation is front-loaded.

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 single-parameter pure function with no output schema, an agent still lacks the return shape (hex string? prefixed?) and the canonicalization rules. Those are the two facts needed to actually use the fingerprint as reproducible evidence.

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 100% and the schema already enumerates every accepted JSON type, so the schema does the heavy lifting. The description's 'a JSON value' is consistent but adds no new semantics such as key-ordering or number-normalization behavior.

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 and resource: computes a canonical SHA-256 fingerprint of a JSON value. It is unmistakable against siblings, none of which do hashing. The only ambiguity is what 'canonical' means (which canonicalization scheme), which matters for reproducibility.

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?

'to cite as evidence' implies the intended use case, and '(nothing stored)' implies it is a pure computation. But there is no explicit when-to-use vs. when-not, and no alternatives are named (none of the siblings overlap, so this is acceptable but not instructive).

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