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

With no annotations provided, the description carries the burden of behavioral disclosure. It reveals the return shape (polymorphic envelope with four fields), which is helpful. However, it does not explicitly state that the operation is read-only, nor does it mention auth requirements or error behavior. For a lookup tool, the risk is low, but the description does not fully disclose side-effect potential or constraints.

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, efficient sentence that leads with the action ('Look up') and specifies the resource and return content. There is no redundancy or filler, making it highly concise and well-structured.

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?

Given the tool has only one parameter, no output schema, and no annotations, the description provides substantial context by listing the expected return fields. It covers the core purpose and outcome. It could additionally explain what happens for invalid IDs or not-found cases, but for a simple get lookup, the coverage is strong.

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% because the only parameter (mii_id) is described as 'MII identifier'. The description does not add further semantic detail about the parameter, such as format, examples, or constraints. Baseline 3 is appropriate since the schema handles parameter documentation adequately.

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 function: 'Look up a Morph Identity Index (MII) record.' It uses a specific verb ('look up') and resource ('MII record'), and further specifies the return content (capabilities, shape, supermodel parent, trust score). This distinguishes it from sibling tools like morph_get_supermodel, which targets a different resource.

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 tool is for looking up MII records but provides no explicit guidance on when to use it versus alternatives. There is no mention of exclusions or when to prefer other tools like morph_get_supermodel. The intended usage is clear from the resource type, but explicit differentiation is absent.

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