diff

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

No annotations are provided, so the description must disclose behavioral traits. It only says 'diff,' implying a read-only comparison, but does not explicitly confirm no side effects, destructive actions, or required permissions. The description fails to compensate for the lack of annotations.

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 extremely concise at three words. While it could be more informative, it avoids redundancy. It is front-loaded and wastes no words, but the brevity sacrifices necessary detail for a tool with 24 parameters.

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's complexity (24 parameters, no output schema, many device selectors), the description is severely incomplete. It does not explain the output format, how to supply two snapshots (e.g., via files or in-memory), or any contextual details like whether it requires a running session. An agent would struggle to use this tool correctly.

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 input schema covers 71% of parameters with descriptions, which is moderately high. The tool description does not add any meaning beyond the schema; it provides no insight into how parameters like 'session', 'device', or 'stateDir' affect the diff operation. Baseline score of 3 is appropriate given the schema coverage.

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?

Description states 'Diff accessibility snapshots,' indicating the tool computes a difference between snapshots. However, it does not clarify what two snapshots are compared or how they are provided (e.g., via file paths or previous results). The purpose is clear at a high level but lacks specificity to distinguish it from a simple snapshot retrieval or comparison tool.

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?

No guidance is given on when to use this tool versus alternatives like 'snapshot' or manual comparison. There is no mention of prerequisites, such as needing previous snapshots, or how the diff output can be interpreted. The description provides zero usage context.

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