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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds no behavioral context beyond that — it does not name the canonicalization algorithm (e.g. RFC 8785 JCS, sorted keys, number handling), which is exactly the kind of detail that determines whether output is interoperable.

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, front-loaded with the operation, with no filler or repetition. The second sentence (REST endpoint equivalence) is of marginal value but costs almost nothing.

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?

There is no output schema, so the description should specify the return shape — e.g. whether it returns the canonical JSON text, a hex SHA-256 digest, or both — and it does not. Combined with the unspecified canonicalization algorithm and the undocumented parameter, the definition is too thin for correct invocation.

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?

With one parameter at 0% schema description coverage and an untyped schema (`value: {}`), the description carries the full burden and fails it: it never says whether `value` is a JSON object, a pre-serialized JSON string, or an arbitrary scalar. The word 'JSON' in the purpose line is the only weak hint about the input shape.

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+resource (canonicalize JSON) plus the secondary effect (compute SHA-256), which is enough to distinguish it from every sibling tool in the list. It stops short of naming the canonicalization scheme, so the agent knows the operation but not its exact semantics.

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 when-to-use guidance, no mention of when a canonical form or a stable hash is required, and no alternatives or exclusions. The only orientation offered is an equivalence to a REST endpoint, which tells the agent nothing about tool selection.

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