map_locator_to_source

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

The description discloses that it uses the execution stack from the test runner, which is useful internal context. However, with no annotations provided, it does not detail potential limitations, error behavior when no mapping is found, or whether the operation is purely read-only. A more thorough disclosure would be beneficial, but the basic behavior is stated.

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 a single, concise sentence that front-loads the core purpose and specifies the method (execution stack). It contains no fluff and earns its place with essential information.

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 tool has only 2 parameters and no output schema, the description covers the main functionality but could be more explicit about the return format (e.g., file path and line number) and any prerequisites (e.g., requiring a test runner trace). It is close to complete for a simple mapping tool, but a few details are missing.

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?

The schema already provides full descriptions for both parameters (trace_path and action_index) with 100% coverage. The description mentions 'action index' but does not add significant extra meaning beyond the schema, such as how to derive the index from the trace or edge cases. Baseline 3 is appropriate.

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 function: mapping a failing browser interaction or action index to a specific line of code in the test file using the execution stack. This is a specific verb+resource that distinguishes it from siblings like get_trace_summary or get_causal_chain_for_failure, which focus on other aspects of the 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 usage when needing to locate the source line for a failing action, with an optional action_index parameter to target a specific step. However, it does not explicitly mention alternatives or when not to use this tool, so it gives clear context but no exclusions.

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