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

Annotations cover the safety profile (read-only, idempotent, non-destructive), and the description still adds substantial behavioral context: depth and node caps, the truncation signal via totalDescendants, the exact node fields returned, and the agentBrief toggle. This is well beyond what the annotations provide.

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 purpose, then routing alternatives, then caps and return shape. The field enumeration is dense but directly tells the agent what it receives, so every sentence earns its place.

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 hierarchy-fetch tool with no output schema, the description covers purpose, alternatives, caps, truncation detection, and returned fields, which is everything needed to call it correctly and interpret the result.

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% and the schema already documents default=3, max=5, root depth=0, and includeAgentBrief behavior. The description mostly repeats those defaults, adding only the global 200-node cap and a restatement of agentBrief, so baseline 3 is appropriate.

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 ('Return a task and all its descendants up to a given depth') and explicitly distinguishes itself from siblings by name (get_plan for the full tree, list_tasks for one level). An agent can select it correctly 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 use case ('when you have a root task id and want parent + children + grandchildren in one call') and names the two alternative tools with the exact conditions that select them. No routing decision 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.