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

The description discloses that the tool is read-only, reads all vdd/ artifacts, and does not modify files. This aligns with the annotations (readOnlyHint=true, idempotentHint=true) and adds the artifact scope. It doesn't describe the return format, but the read-only and idempotent behavior is transparent, which is sufficient given the 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?

Two sentences, each carrying weight. The purpose is front-loaded, and the usage guidance follows immediately. No filler 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?

The description covers purpose and usage, but given the tool has 10 optional parameters and no output schema, it leaves out how parameters influence behavior. It also doesn't specify the return structure (though the tool name suggests a matrix). For a read-only tool with many apparently extraneous parameters, this incompleteness could confuse an agent about what to pass. However, the core function is well explained, so it's above minimal but not fully complete.

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 100% (baseline 3), but the description adds no parameter-specific guidance. The schema contains many generic parameters (taskId, feature, statement, etc.) that appear unrelated to matrix generation, and the description doesn't clarify which parameters are relevant or how they affect output. This is a significant gap: an agent cannot infer whether to pass projectRoot only or other fields, leading to potential misuse.

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 function: generating a bidirectional V→S→T→SP→PL→TK traceability matrix. It names the specific resource (vdd/ artifacts) and distinguishes it from siblings (vdd_analyze for per-feature spec metrics, vdd_validate for release-readiness). This leaves no ambiguity about what the tool does.

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?

Explicitly states when to use the tool ('any time to inspect coverage') and explicitly names two alternatives (vdd_analyze for per-feature metrics, vdd_validate for gates validation). This gives clear decision criteria for an agent choosing among siblings.

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