capability_diff

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, and the description reinforces this with 'Read-only.' It adds useful behavioral context by stating what the comparison produces and what a mismatch means, though it does not go into deeper details like response format or potential failure modes. This is acceptable given the annotation coverage.

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 three sentences with no filler. It front-loads the read-only nature, then states the action, outputs, and interpretation. Every sentence contributes meaningful 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?

For a simple, zero-parameter read-only tool, the description is largely complete: it names the outputs and their diagnostic meaning. There is no output schema, but the description compensates well. A more advanced agent might want an example, but none is necessary for correct invocation.

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 tool has zero parameters and the schema is empty with 100% coverage, so no parameter documentation is needed. Per the baseline for zero-parameter tools, a score of 4 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 states a specific operation ('Compare the live worker tool surface against a fresh probe of the current build'), identifies the resource being compared, and names the concrete outputs ('added/removed/changed tool names and fingerprintMatch'). This clearly distinguishes it from sibling tools like machine_status or runtime_info.

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 gives clear context for when this tool is relevant: checking whether the worker serves a stale build by comparing live surfaces to a fresh probe. It does not explicitly name alternatives or exclusion conditions, but the intended diagnostic use is strongly implied.

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