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

Annotations already declare destructiveHint=true and idempotentHint=true, and the description goes beyond them with what an agent actually needs: a non-existent variable is a not-found error rather than a silent success, the org path requires an admin-scoped token, and the call is audit-logged. It also states the return shape, which matters because there is no output schema.

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?

Sentences are short, front-loaded with the action, then the required scoping shape, then failure and return semantics. Every clause carries information; the only slight redundancy is restating the return value after already saying a missing variable is an error.

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 destructive, six-parameter tool with zero required parameters and no output schema, the description covers scoping, auth requirements, failure semantics, audit logging, and return value. The remaining hole is the undocumented `id` parameter as an alternative to `name`.

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%, so the baseline would be 3, but the description adds real meaning by explaining the conditional combinations of otherwise all-optional parameters — something the schema cannot express. It loses a point for describing deletion 'by name' while never mentioning the schema's `id` alternative.

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?

Opens with a specific verb and resource ('Delete an Actions variable'), and the resource is narrow enough (variables, not secrets) to separate it from neighbours like merjax_delete_repo_secret and merjax_delete_loop_secret. It then enumerates the three scoping modes, so an agent knows exactly what class of object this acts on.

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 gives concrete routing rules for invocation: owner+repo for repository variables, owner+repo+environment for environment variables, org for organisation variables. The one gap is that it never explicitly contrasts with merjax_set_variable or merjax_get_variable, but the operation is unambiguous enough that the missing sibling callout is minor.

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