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

Annotations already declare destructiveHint=true and openWorldHint=false; the description corroborates by stating 'Overwrites the spec file', which tells the agent prior content is lost. It does not discuss permissions or failure modes, but the safety profile is well covered.

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?

Front-loads the phase, output artifact and content, then usage routing, then parameter relationships. Dense but every clause carries information; the trailing parameter-relationships sentence is borderline long but earns its place.

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?

Output schema exists so return values need no explanation, and the description covers overwrite behavior, alternative tooling, the ID format and cross-phase consistency. Nothing an agent needs to invoke it correctly is missing.

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% so the baseline is 3, but the description adds cross-tool semantics the schema lacks: feature must match the value passed to vdd_clarify/vdd_plan/vdd_tasks, and actionItemId is optional when authoring from a freeform description.

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?

States a specific verb+resource (generate vdd/specs/<id>/spec.md) and enumerates the artifacts produced (user stories, boundaries, AC, MoSCoW, NFRs). It places itself explicitly as 'VDD Phase 4' and distinguishes itself from vdd_clarify for leftover clarification markers.

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?

Gives explicit when-to-use ('for a NEW spec') and when-not ('to resolve leftover [NEEDS CLARIFICATION] markers use vdd_clarify instead'), plus a shortcut path (pass actionItemId or a freeform description to skip the V/S/T chain).

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