coverage_compare

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It clearly states that the tool compares sessions and reports improvement direction along a defined maturity path (GAP→PARTIAL→DETECTABLE→COVERED), which gives an agent a good sense of expected behavior. It does not explicitly state that the operation is read-only, but 'Compare' and 'Shows' strongly imply no mutation.

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?

Two sentences, no filler, and the primary purpose is front-loaded. The second sentence provides a practical example that adds contextual value without padding.

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?

The tool is simple: two required parameters, no nested objects, no output schema, and no annotations. The description explains what it compares, what it returns, and even gives a representative question it answers, making it sufficiently complete for an agent to invoke 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 schema already describes both parameters at 100% coverage, so the baseline is 3. The description adds meaningful semantic context by defining session_before as the baseline and session_after as the comparison after adding new log sources, which helps the agent map the parameters correctly to the use case.

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 a specific action—comparing coverage between two assessment sessions—and describes the output (technique improvements and gaps closed). This is distinct from sibling tools like analyze_coverage or identify_gaps, which operate on a single session, and the example use case reinforces its unique purpose.

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 a concrete scenario ('If I add Sysmon, how much does my coverage improve?') that tells an agent when to use this tool. It does not explicitly mention when not to use it or name alternatives like analyze_coverage, but the two-session comparison framing is clear enough for typical selection.

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