start_trace

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

No annotations are provided, so the description carries the full burden. It discloses the CDP category filter and the one-trace constraint, but does not explain what happens if a trace is already active (e.g., error or override), potential side effects on performance, or the need for subsequent 'stop_trace'.

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 short (two sentences plus a parameter note) and front-loaded with the core purpose. It avoids redundant information but could be slightly more structured (e.g., separate lines for behavior and parameter).

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?

Given the presence of an output schema, the description need not detail return values. However, it omits the workflow context: that the trace must be stopped with 'stop_trace' to retrieve results, and what the output schema represents (e.g., trace data). This leaves the agent without a complete action sequence.

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?

With 0% schema description coverage, the description adds significant meaning: it explains that 'categories' is a comma-separated CDP filter and that an empty string uses the default profile. This goes beyond the basic type and default value in the schema.

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 the tool's action ('Begin recording a performance trace'), specifies the target ('the current tab'), and includes a key constraint ('Only one trace can be active per tool instance at a time'). This distinguishes it from sibling tools like 'stop_trace'.

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 implies the tool should not be used if a trace is already active ('Only one trace can be active...'), but it does not explicitly state prerequisites, error conditions, or when to prefer alternatives. It provides some context on the categories parameter but lacks concrete guidance on when to invoke.

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