compare_profiles

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

Annotations already declare readOnlyHint=true and idempotentHint=true, indicating safe read operations. The description adds no additional behavioral context (e.g., no mention of file permissions, error conditions, or output size). It does not contradict annotations, so a baseline score of 3 is appropriate.

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?

Single sentence that is front-loaded with the action and output. No redundant words or extraneous details. Every word serves a purpose.

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 explaining return values and the clarity of the description for a straightforward comparison tool, the description is mostly complete. It lacks details on prerequisite file existence or error scenarios, but these are less critical with annotations indicating safe operation.

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?

Input schema has 100% coverage with descriptions for all parameters. The description does not add extra semantics beyond 'compare' and 'show percentage changes', which are already implied. The parameter 'top_n' is described in schema, so no added value from description.

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 uses specific verb+resource: 'compare two speedscope profiles' and specifies output 'show percentage changes'. It clearly distinguishes from sibling tools like analyze_profile (single profile analysis) and top_profile (single profile top frame).

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 no guidance on when to use this tool versus alternatives. No mention of context such as needing two distinct profiles or that it is for comparative analysis. The presence of sibling tools like analyze_profile implies a distinction, but no explicit instructions.

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