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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so safety and determinism are structured. The description still adds real value with 'no storage' (nothing is persisted) and 'canonicalizes' (implying the same logical value yields the same hash), which are the key behavioral traits for citing a hash as evidence.

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 with zero filler; the core action and its distinguishing property (no storage) are front-loaded, and the usage trigger follows immediately.

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, fully annotated utility, the description covers what it does, that it persists nothing, and when to use it. The only gap is that canonicalization rules that determine hash reproducibility are unspecified, which matters somewhat for an evidence-citing tool but is not critical.

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 single 'value' parameter is fully described as any JSON value, so the schema does the heavy lifting. The description adds no extra semantics such as canonicalization rules (key ordering, number normalization), so this is the baseline 3 rather than a higher score.

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 pair (canonicalize, fingerprint), the resource (a JSON value), and the exact output (SHA-256 fingerprint). An agent can tell precisely what this does without opening the schema, and the siblings (need/capability/shop tools) are entirely unrelated so no differentiation is required.

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?

Explicitly frames the use case with 'Use when: you need a reproducible hash to cite as evidence,' giving a clear trigger condition. It does not name alternatives or exclusions, but no sibling competes for this function, so the missing exclusion clause is minor.

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