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

Annotations already declare readOnlyHint: true, so the read-only nature is covered. The description adds the prerequisite of project context and clarifies the output includes aliases, which is useful behavioral context beyond the annotations.

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 zero waste. The core action is front-loaded, followed by the alternative usage, then the requirement. Every word contributes to effective agent guidance.

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 zero-parameter list tool with readOnlyHint annotation, the description covers the purpose, the alternative, and the prerequisite. No return format is specified, but the output is implied by the description (aliases), and no other details are needed 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?

There are no parameters (schema coverage is vacuously 100%), so the baseline of 4 applies. The description doesn't need to explain parameters, and it doesn't attempt to add irrelevant details.

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 ('List') and resource ('organization fixtures the active project has imported'), and specifies the output ('with the alias each is referenced by'). It explicitly differentiates from list_org_fixtures, making the tool's scope unmistakable.

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?

Provides explicit when-to-use guidance ('Use this for what this project has imported') and an alternative with a clear distinction ('for what is available to import use list_org_fixtures'). Also notes the prerequisite 'Requires project context', leaving no ambiguity about invocation conditions.

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