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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description still adds value beyond them: it reinforces 'never edits tasks.md' and discloses the completion-marker return behavior when no tasks remain. It stops short of describing pagination or ordering of tasks, keeping it at a 4.

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 phase tag and the core action, then constraints, then routing to siblings. Dense and mostly earned, though the closing 'Parameter relationships' sentence is slightly redundant with material already stated inline.

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-value detail is unnecessary. The description covers purpose, safety, usage timing, sibling routing, and parameter linkage — everything an agent needs to call it correctly in this multi-phase workflow.

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 description coverage is 100%, so the baseline is 3. The description goes further by documenting cross-tool parameter relationships: 'feature must match the spec directory' and 'the returned taskId (TASK-###) is the argument to vdd_implement', which the schema does not state.

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 ('Read vdd/specs/<feature>/tasks.md and return the next uncompleted task'), including the edge case of a completion marker. It names sibling tools (vdd_tasks, vdd_implement) so an agent can distinguish it from near-neighbors 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?

Explicitly says when to use it ('before each implementation session to keep context isolated') and names the alternatives with their selecting conditions: vdd_tasks to regenerate the list, vdd_implement to execute the returned task. 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.