List Fixtures

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

With readOnlyHint=true already declared, the description correctly avoids repeating that. It adds meaningful behavioral context: the operation is scoped to 'project-owned' fixtures, requires project context, and clarifies what fixtures are. This goes beyond the annotation without contradicting it.

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?

The description is brief and front-loaded with the core action and scope. The second sentence explaining fixtures is helpful context, and the final requirement is stated concisely. The 'E84:' prefix adds no apparent value and slightly dilutes clarity, keeping it from a 5.

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 simple list operation with no required parameters and a well-documented schema, the description covers purpose, scope, and a key prerequisite. It does not describe the return format, but no output schema is present and the tool is straightforward enough that this is a minor gap. Explicit sibling differentiation would make it fully complete.

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%, so the schema already documents skip, take, and tagFilter with descriptions and defaults. The tool description adds no parameter-level detail beyond defining fixtures, which aligns with the baseline of 3 when the schema carries the semantic load.

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 clearly states a specific verb ('List') and a specific resource ('project-owned fixtures in the active project'), and adds a concise definition of fixtures as structured test data. It is clear and unambiguous, but it does not explicitly differentiate itself from siblings like list_fixture_imports, get_fixture, or get_fixture_usage, so it stops short of a 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?

The prerequisite 'Requires project context' gives a useful condition for when this tool can be called, and the scope 'in the active project' implies the intended environment. However, the description offers no guidance on when to use this tool instead of a sibling such as list_fixture_imports or get_fixture, so the usage guidance is only implied rather than explicit.

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