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

Annotations already declare readOnly, idempotent, closed-world, so the description is free to spend its words on output semantics — that the result includes migration steps and deprecations, not just a diff. It does not mention that omitted versions default to first/latest release, but the schema covers that.

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?

A single sentence, front-loaded with the agent-facing question it answers, followed by the concrete payload. Nothing redundant.

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 no output schema, the description carries the return-value burden and does so by naming the content (breaking changes, migration steps, deprecations, spans of releases). Slightly incomplete on default-version behavior, though the schema covers it.

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 each parameter (including defaults and the markdown/json enum) is already documented in the schema. The phrase "every release after `from` up to `to`" gently reinforces the inclusive range but adds little beyond the schema.

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 resource-level operation (diffing two versions) and enumerates what the answer contains: breaking changes with migration steps, deprecations, and every release between `from` and `to`. The range semantics distinguish it from single-release siblings like get_release and list_releases.

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?

The framing "what changed between two versions, and what do I need to change?" makes the upgrade-path use case explicit, and the changelog parameter routes discovery to search_changelogs. No explicit when-not-to-use or named alternative is given, so it falls short of a 5.

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