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

Annotations already declare destructiveHint=true and openWorldHint=false, and the description reinforces this with 'Overwrites tasks.md', telling the agent exactly what is destroyed. It also discloses ordering and cross-tool parameter coupling. It stops short of describing output/return behavior or whether a partial run leaves the file in a bad state.

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-loaded with the action and target file, then prerequisite, then alternative, then parameter coupling. Every sentence carries a distinct piece of information; no filler.

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?

For a destructive write tool with an output schema already present, the description supplies everything an agent needs: what it writes, that it overwrites, the prerequisite phase, the correct sibling for read-style access, and cross-phase parameter consistency.

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 a genuine cross-tool constraint beyond the schema: 'feature must match the value passed to vdd_plan'. It adds no further format detail because the schema already documents kebab-case and projectRoot semantics.

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 artifact: 'Break the plan into atomic test-first tasks in vdd/specs/<feature>/tasks.md', including the phase number and file written. It also names the sibling it must not be confused with (vdd_get_next_task), so an agent can distinguish it without opening schemas.

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 ('Requires plan.md; run after vdd_plan') and an explicit alternative with the selecting condition ('To fetch the next uncompleted task from an existing tasks.md use vdd_get_next_task instead of re-running this'). Nothing about when to use it 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.