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

'Overwrites these files' directly reinforces the destructiveHint annotation by naming what is destroyed, which is valuable beyond the boolean flag. It also discloses cross-tool state coupling (the spec must already exist). It stops short of covering failure behavior or whether the whole directory is replaced vs. individual files, so it earns a 4 rather than a 5.

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 and outputs before the prerequisites, and every sentence carries information (artifact list, overwrite warning, ordering, parameter linkage). It is a single dense paragraph rather than a broken-out structure, which slightly hurts scanability for a multi-part rule set.

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, and the description already covers prerequisites, ordering, side effects, and parameter coupling. Remaining gaps (error/failure cases, whether a partially-specified feature is valid) are minor for a generate-a-blueprint 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 100%, so the baseline is 3, but the description adds relational meaning the schema cannot express: `feature` must match the value passed to vdd_specify and vdd_tasks, and projectRoot consistency across phases is emphasized. That cross-parameter, cross-tool constraint is genuine added value.

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 (generate the technical blueprint) plus the exact artifacts produced under vdd/specs/<feature>/ (plan.md, data-model.md, contracts/), and places itself in the phase sequence. This is distinguishable from vdd_specify, vdd_clarify, and vdd_tasks without opening any schema.

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 an explicit prerequisite (an existing spec for the feature), the required ordering (after vdd_specify/vdd_clarify, before vdd_tasks), and a fallback routing instruction ('if no spec exists yet, run vdd_specify first'). Nothing about when-to-use 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.