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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description only needs to add context, and it does: pricing ($0.10 USDC per call, x402 or prepaid credits) and the free-trial exclusion are behavioral traits an agent cannot get from the annotations or schema. It does not contradict the annotations, though it says nothing about latency or per-call output size.

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 core purpose, then a dense but relevant enumeration of report contents, then the pricing constraint. It is a single long paragraph rather than a list, but every clause carries information and nothing is padding.

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, and the description covers what the report contains plus cost and the read-only/open-world safety profile is in annotations. Remaining minor gap is routing versus sibling upgrade/audit tools and any note on how versions are resolved.

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 four parameters (name, from, to, ecosystem) are already fully documented with examples and defaults. The description restates the from/to/name concept ('package X from version A to B') without adding format, ecosystem-selection, or version-resolution guidance beyond the schema, so baseline 3 applies.

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: it produces an upgrade report for moving a named package from version A to B, and the enumerated contents (breaking changes, migration guide, peer requirements, vulnerabilities, community issues, cited plan) make the deliverable unambiguous. It does not, however, distinguish itself from nearby siblings such as package-upgrade, dependency-report, or compat-check, which an agent must disambiguate itself.

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 description implies the use case ('fix this dependency upgrade' report) but never states when to choose it over package-upgrade, package-changes, or compat-check. It does add one concrete usage constraint — paid only, not available in the free trial — which is genuinely useful, but that is a billing rule rather than routing guidance.

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