Provide Inlay Hints

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

Annotations already declare readOnlyHint=true, so the description does not need to reiterate safety. It adds value by specifying the types of hints returned (inferred types, parameter names, return types), enriching behavioral understanding beyond the annotation.

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 extremely concise with three short sentences, each serving a clear purpose: what it does, what it shows, and when to use it. No unnecessary words.

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 no output schema, the description adequately conveys what the tool returns (types, parameter names, return types). However, it could be more precise about the response structure (e.g., array of hints with positions). Still, it is fairly complete for a simple read-only tool.

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?

All three parameters are fully described in the input schema (100% coverage). The description adds no additional meaning, examples, or constraints beyond the schema, so baseline 3 is appropriate.

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: 'Get inlay hints (inline type annotations) for a range.' It specifies the verb, resource, and scope, and distinguishes from sibling tools by focusing on a specific kind of information (inferred types, parameter names, return types) not provided by other tools like completion or quickinfo.

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 only implicitly suggests usage by stating it is 'useful for understanding what TypeScript infers.' It lacks explicit guidance on when to use this tool versus alternatives (e.g., quickinfo, typeDefinition) and does not state when not to use it.

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