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

Annotations already declare idempotentHint=true, readOnlyHint=false, and destructiveHint=false, so the safety profile is covered. The description adds useful detail that retries yield the same ids and external refs, but it repeats the annotation's idempotency claim and remains silent on collision behavior for existing keys, permission requirements, or what happens to pre-existing milestones.

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?

Two short sentences with zero filler; the core action and its idempotency guarantee are front-loaded and nothing is wasted.

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 non-readonly initialization tool with 0% parameter documentation, no output schema, and non-trivial nested input, the description omits too much: it does not cover required input, conflict handling for existing milestone keys, or what the caller receives back.

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 0% and the description adds nothing about the two parameters. Neither engagement_id (the required UUID) nor the milestones array with its key/title/due_date/order_index fields is explained, so an agent must infer all semantics from the raw schema alone.

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 (initialize) and resource (stable engagement milestones) with an explicit qualifier (idempotent). An agent can identify the operation, but the description does not distinguish it from the sibling update_consulting_milestone or explain what 'stable' milestones mean versus ordinary ones.

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?

No when-to-use guidance, no prerequisites, and no routing to the obvious alternative (update_consulting_milestone). The idempotency note implies safe re-invocation but never says when this tool should be called versus updating or listing milestones.

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