Diff snapshots

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

The description explains what it returns (only changed lines) and notes it is a diff operation. The readOnlyHint annotation confirms it does not alter state. However, it does not describe edge cases like what happens if no snapshot exists, or the exact return format, leaving some minor ambiguity.

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 concise, with two sentences that convey the core functionality and a key benefit. No unnecessary words or redundancy.

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?

For a simple tool with one optional parameter and no output schema, the description provides sufficient context to understand its purpose and basic behavior. It lacks explicit error handling or return structure details, but these are not critical for a straightforward diff 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?

The single parameter contextLines is fully described: it specifies the number of unchanged lines to show around each change, with a clear default. Schema coverage is 100%, and the description adds meaningful detail beyond 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 purpose: to show only changes since the last snapshot. It also provides context ('cheapest way to check the effect of an action'), which distinguishes it from a full snapshot and makes its intent unambiguous.

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 by mentioning 'since the last snapshot' and 'effect of an action', but it does not explicitly state prerequisites (e.g., that a prior snapshot must exist) or contrast with sibling tools beyond the implied distinction from browser_snapshot. Still, the guidance is clear enough for most agents.

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