quest_perf_diff

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 transparently states that the tool returns metric deltas and verdict change, implying a read-only comparison operation. However, it does not explicitly disclose the absence of side effects or detail behavior for invalid/missing files. For a diff tool, the core behavior is adequately described, but some behavioral context is left to inference.

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 two sentences, front-loaded with the primary action and resource, and every phrase adds value. It avoids restating the tool name or schema details, and the example use case is efficient.

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 simple two-parameter interface and no output schema, the description is mostly complete: it explains the input source (JSON files from quest_perf_session), the purpose (comparison), and the output (metric deltas and verdict change). It could add nuance about file path expectations or exact format, but this is not critical for basic usage.

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 0%, but the parameter names 'before_session_path' and 'after_session_path' are self-explanatory. The description adds valuable context by specifying these are JSON files from quest_perf_session and reinforcing the before/after relationship, which compensates for the lack of schema descriptions.

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 compares two recorded perf sessions, with a specific verb ('Compare') and resource ('recorded perf sessions (JSON files from quest_perf_session)'). It also gives a concrete use case (before/after an optimization) and distinguishes it from sibling tools like quest_perf_session (which records) and quest_performance (which likely monitors).

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 clearly implies when to use this tool: when you have two saved perf sessions and want to compare them, especially before/after an optimization. It does not explicitly name alternatives or state when not to use it, but the context is strong enough to guide selection among the sibling tools.

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