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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It discloses nothing: no side effects, no return shape, no read-only nature, no error behavior, no access patterns. The only behavioral hints (discarded values, no disk access) live in the schema's parameter descriptions, not in the tool description — so the description itself contributes no transparency.

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 text is short, but this is underspecification rather than conciseness — four meaningful words cannot earn credit for tight writing when they fail to say what the tool does. There is no structure to praise: no front-loaded action, no scoping, no alternative routing. Minimal length without minimal required content is a deficiency.

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 tool with 10 parameters, no annotations, no output schema, and 31 siblings, this description is drastically incomplete. An agent cannot determine what inputs to provide, what response to expect, or how this differs from dozens of similar tools. Even with 100% schema coverage on parameters, the missing tool-level purpose makes the definition inadequate for reliable selection and invocation.

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 schema already documents all 10 parameters in reasonable detail. Per the baseline rule, a 3 is appropriate. The description adds nothing about parameters, but it also doesn't need to; the weak point is that the tool description doesn't explain how these ten heterogeneous parameters relate to a 'language tag yi' purpose, so the parameter set feels disconnected from the stated tool identity.

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 'ISO 639 language tag yi' is essentially a gloss of the tool name 'lang-yi' — it states what 'yi' denotes but never states an action. There is no verb indicating whether the tool validates, resolves, normalizes, or returns data about a language tag. It also fails to distinguish itself from 31 siblings (e.g., normalize-url, validate-json, domain-shape), and the 10-parameter schema of unrelated fields (url, city, feed, json, website) makes the actual purpose even more opaque.

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 offers zero guidance on when to use this tool versus any alternative. No sibling is named, no condition or context is given, and no exclusion is stated. An agent has no basis to decide between lang-yi and the many other checker-style siblings in the list.

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