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

Annotations already declare readOnlyHint=true, openWorldHint=false, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description's 'Makes no network requests' largely restates openWorldHint=false, though it usefully signals that explanations are static/local. It also hints at the response shape (explanation plus suggested fix), but with an output schema present that is supplementary rather than essential.

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 carrying purpose, code provenance, output intent, and a network guarantee, with no filler. The most decision-relevant information (what it explains and where codes come from) 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, read-only lookup tool with an output schema, this is close to complete: the agent knows the input source, the output nature, and that calling it has no side effects. Minor gap: it does not say what happens with an unknown or malformed code.

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 there is a single required parameter with a documented maxLength and examples. The description repeats the same examples without adding new syntax, casing, or lookup-failure semantics, so baseline 3 is appropriate.

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 states a specific verb and resource: it explains a finding code 'in plain words, with a suggested fix'. It also clarifies where codes come from ('returned by any Store Canary tool'), which separates it from the check_* siblings that produce findings rather than explain them. It stops short of explicitly contrasting itself with those siblings, keeping it at 4 rather than 5.

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?

It clearly establishes the trigger condition: the agent has a finding code from a prior Store Canary result and wants a human-readable explanation. It gives concrete example codes (ssl_hsts, exposure_debug_log). There is no explicit 'do not use this for X' guidance, but no sibling performs a comparable function, so the context is sufficient.

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