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

With no annotations, the description must carry the behavioral burden. It discloses that the value is discarded, which hints at a side-effect-free length check, but it does not explain whether validation succeeds, what the output is, or whether any external lookup occurs.

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 extremely short, but it is under-specified rather than efficiently structured. A few more words stating the validation action and expected input would make the sentence worth its place.

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?

The schema descriptions provide substantial parameter-level context, but the main description does not state the validation logic, which parameter to supply, or what response to expect. For a validation tool with no output schema and no annotations, this remains a significant gap.

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 of the nine parameters already has a description, so the baseline applies. However, the tool description does not clarify which of the nine optional parameters is the intended ObjectId value, and it adds no semantics 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?

The description is a noun fragment ('Mongo ObjectId hex length, value discarded') rather than a specific verb+resource statement. It hints at ObjectId validation but never states whether the tool checks, returns, or transforms the input, leaving the actual operation ambiguous.

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?

There is no guidance about when to use this tool versus sibling shape/validation tools such as jira-key-shape or wiki-title-ok. The phrase 'Mongo ObjectId' implies a domain but does not articulate conditions, alternatives, or exclusions.

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