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

Annotations already declare readOnly/idempotent/openWorld/non-destructive, so the bar is lower, and the description still adds real context: the data source (endoflife.date), that it is community-maintained and typically refreshed daily, that preview/beta releases are filtered out, and that a call costs 1 credit. It does not say what happens when the product slug is unknown or not found, which is the main behavioral gap.

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?

It is front-loaded with the user-facing question, then the return payload, then caveats (source, freshness, beta exclusion, cost). Every sentence carries information, though the parenthetical cost and source notes could be tightened and the phrase 'release cycle, its latest patch version and date, release date' is slightly repetitive.

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 usefully enumerates the returned fields and states data provenance and freshness, which is what an agent needs to trust and cite the answer. The remaining gap is error/edge-case behavior (invalid slug, missing product) and whether historical cycles are ever included, but for a one-parameter read tool this is close to complete.

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% and the single 'product' parameter already documents the required slug with examples (python, nodejs, postgresql). The description only refers to 'a product' generically and adds no format guidance, aliasing advice, or example slugs beyond the schema. Baseline 3 is correct when the schema carries the parameter documentation.

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?

The description opens with a specific question-form verb+resource ('What is the latest version of a product right now?') and then enumerates exactly what is returned: newest release cycle, latest patch version and date, release date, support status, EOL date. This is concrete enough to separate it from sibling EOL tools like eol_unsupported_releases or eol_product_search, though it never names those siblings explicitly to sharpen the contrast.

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?

It implies when to use it — whenever a user asks about 'the latest Python/Node/PostgreSQL' and stale training data is a risk — and notes that preview/beta releases are excluded. However, it gives no explicit when-not guidance and never routes the agent to eol_product_search or eol_unsupported_releases for the cases this tool does not cover (unsupported versions, browsing products).

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