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

Annotations already indicate read-only and non-destructive behavior, so the description adds value by stating the deprecation with a specific removal date (2026-12-31) and the fact that it returns 'undetermined' for lines without published end-of-life. This goes beyond the annotations to disclose lifecycle and edge-case behavior, though it doesn't detail all potential return structures.

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?

The description is a single dense paragraph, efficient but slightly front-loaded with deprecation notice before the core function. It avoids redundancy and includes necessary caveats in a few sentences. Slightly better structure would separate the deprecation warning from the tool's function, but it's appropriately sized.

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 read-only query tool with no output schema and two parameters, the description explains the output categories (supported, maintenance, EOL) and the undetermined case, which is essential for correct use. It also provides upgrade-cycle context. However, it doesn't mention specific product names or version formats, which could be important given the deprecation warnings, but overall it's sufficiently complete for an agent to make a call.

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%, so the description must compensate. It mentions 'product' and 'version' implicitly but does not define allowed formats or examples. Given only two simple string parameters, the description could be more explicit about valid values (e.g., version syntax), but the minimal complexity slightly mitigates the gap. Baseline is 3 due to zero coverage.

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 clearly states the tool's purpose: to check release support status, including specific categories (supported, security-fix-only, past end-of-life) and output details (dates, upgrade cycles). It distinguishes itself from sibling tools like compat_check and discover_daystruct_capabilities by explicitly naming them and framing this as deprecated. The verb 'check' plus resource 'release support' is specific and unambiguous.

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 explicitly warns the tool is deprecated and directs users to alternatives (discover_daystruct_capabilities and compat_check) for building purposes. It clarifies when to use (given a product and version) and what to expect (undetermined if no end-of-life published). This provides clear usage context and appropriate routing to siblings.

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