rails_get_concern

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 still adds behavioral value by disclosing the two operating modes: omitting name yields a browsable listing of all concerns, while naming one yields detail, and detail:"full" pulls in source code (i.e. a materially larger response).

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?

Three sentences, front-loaded with purpose, then usage, then parameter mechanics; no filler. The use-when trio is slightly boilerplate but short enough to earn its place.

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?

With annotations carrying the safety profile, a fully documented schema, and no output schema, the description covers what an agent needs: what is returned, the list-vs-detail mode switch, and filtering. Only the exact listing shape for the no-name case is left implicit.

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 each parameter is already well documented there, so the baseline is 3. The description illustrates name usage ('Searchable') but its filter examples are thinner than the schema — it lists only type:"model" or type:"controller" while the schema enumerates model, mailer, service, lib, other, and all — so it adds little and slightly narrows the picture.

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 (get ActiveSupport::Concern details) and enumerates the payload: public methods, included modules, and including models/controllers. That is clear, but it never names a sibling (e.g. rails_get_model_details or rails_search_code) to disambiguate when a concern-level view is the right choice.

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?

Explicit 'Use when:' clause gives three concrete situations (understanding shared behavior, checking interfaces, finding usages), which is real context rather than a restatement. It stops short of when-not-to-use guidance or naming alternatives, so it lands just below the top band.

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