Explain a module config file

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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds real value by stating what the answer contains: purpose, location (folder and area), XSD URN, and documentation pages — which the annotations cannot convey.

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 sentences, with the purpose and scope front-loaded before the usage hint. The file-type list is long but each item earns its place by disambiguating scope; there is no filler.

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 no output schema, the description is nearly sufficient because it enumerates the expected return content. It stops short of saying what happens for an unrecognized file name or whether the answer is version-specific, but nothing essential to invoking it is missing.

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 schema's own example list already covers path forms like 'etc/adminhtml/system.xml' and 'view/frontend/layout/...'. The description's parallel enumeration reinforces that both bare names and module-relative paths are accepted, marginally improving on the schema but not adding format rules.

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?

Specific verb ('Explain') plus specific resource (Adobe Commerce module config file), with an enumerated list of file types that makes the scope unambiguous. It is clearly distinct from sibling tools like search-docs, read-doc, and scaffold-module.

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?

The final sentence gives an explicit trigger: 'Use it before creating or editing one of these files,' which cleanly positions it relative to scaffold-module and add-db-schema. It does not name an alternative for when an agent already knows the file or wants raw doc content (read-doc/search-docs), leaving that inference to the agent.

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