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

The description says the tool 'Overwrites these files' and generates plan.md, data-model.md, and contracts/, which is a state-modifying write operation, while the annotations declare readOnlyHint=true. This is a direct contradiction that could mislead an agent into treating a destructive overwrite as a safe read; apart from this, the overwrite disclosure itself would have been valuable context.

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 purpose, then artifacts, preconditions, and parameter relationships in a logical order. It is dense but every clause carries information; the long compound sentences are slightly heavy but not 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?

With an output schema present, return values need not be described, and the description still covers artifacts produced, overwrite behavior, sequencing preconditions, and parameter dependencies. An agent has everything needed to call it correctly, aside from the annotation inconsistency noted above.

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 beyond the schema: 'feature must match the value passed to vdd_specify and vdd_tasks'. That relational constraint is not derivable from the schema alone and meaningfully improves correct invocation.

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 and resource ('Generate the technical blueprint') and enumerates the exact artifacts produced (plan.md, data-model.md, contracts/), placing it in a named phase (VDD Phase 5). It is immediately distinguishable from siblings like vdd_specify, vdd_clarify, and vdd_tasks.

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 sequencing: run after vdd_specify or vdd_clarify and before vdd_tasks, and adds an exclusion/fallback ('if no spec exists yet, run vdd_specify first'). The precondition ('Requires an existing spec for the feature') is stated outright.

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