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

The description explicitly states the tool writes and 'Overwrites vdd/tactics.md', which modifies the environment, yet the annotations declare readOnlyHint=true. This directly contradicts the annotation. The rich behavioral detail (prerequisites, hosted-endpoint delegation envelope, filesystem requirement) is otherwise valuable but cannot offset the contradiction.

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?

Well front-loaded: phase and action first, then prerequisites, then parameter relationships. Slightly redundant, repeating 'requires vdd/strategy.md' twice and re-explaining the hosted/stateless limitation, but overall dense and purposeful rather than padded.

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?

An output schema exists so return values need not be explained. The description still covers everything an agent needs: phase ordering, prerequisites, filesystem-capability requirement, cross-tool parameter consistency, and the stateless-endpoint fallback behavior. Complete for a complex multi-mode tool.

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 already 100%, so the baseline is 3. The description adds genuine meaning beyond the schema: projectRoot 'must match the root used by vdd_init, vdd_vision, and vdd_strategize', and it explains the purpose of artifactFiles (hosted endpoint artifact map) and codebaseAudit (host-produced repo scan) with a concrete example.

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 opens with a specific verb+resource ('Audit the existing codebase into vdd/tactics.md') and enumerates the concrete outputs (repo audit, debt assessment, gap analysis, MoSCoW action items, dependency map, infra requirements). It also places itself precisely in the workflow (Phase 3, after vdd_strategize, before vdd_specify), so it is clearly distinguished from siblings like vdd_strategize and vdd_specify.

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?

Explicit when-to-use guidance: 'run after vdd_strategize and before vdd_specify', prerequisite 'Requires vdd/strategy.md', and a routing instruction to 'check with vdd_detect_environment first if the host may lack one'. It also states the alternative path for the stateless endpoint. Nothing is left to inference.

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