profiler_start

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

With no annotations, the description must cover behavior. It states the action and constraints but omits side effects (e.g., performance impact), prerequisites (e.g., profiling not already active), and return values. The description is adequate but not comprehensive.

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 concise sentences with no wasted words. The purpose is front-loaded, and the key constraints are immediately conveyed. List of presets is included inline without unnecessary detail.

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?

The description covers the two modes and constraints. Missing details like return values or error conditions, but given no output schema and the tool's conditional parameters, the description is fairly complete. Sibling tool context is not referenced but implied.

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%, baseline 3. The description adds value by clarifying mutual exclusivity and that some parameters are conditionally required (e.g., 'Required when no preset is given'), which goes beyond the schema definitions.

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 explicitly states 'Start the Firefox profiler,' which is a specific verb+resource. It distinguishes from sibling tools like profiler_stop and profiler_is_active by its action. The two modes (preset vs explicit options) are clearly delineated.

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 description provides clear guidance on the two mutually exclusive modes and lists valid presets. It does not explicitly mention when not to use the tool or suggest alternatives, but the context is sufficient given the sibling tool names.

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