get_diagnostics

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

With no annotations provided, the description carries the full burden and does well by disclosing the default behavior when file_path is omitted (returns diagnostics for all open files) and the prerequisite that files be opened first. It doesn't describe the return format, but the read-only nature is implied by 'Get' and the description adds useful context beyond the bare tool name.

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 concise, consisting of two sentences that front-load the main action and then provide optional behavior and prerequisites. Every sentence earns its place with no redundancy.

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 a single optional parameter and no output schema, the description adequately covers purpose, usage context, and key behavioral nuance (all open files). It could explicitly mention the output structure, but for a diagnostics tool the expected return is generally understood.

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?

The tool description adds no new meaning beyond the input schema: the schema already states that file_path is optional and that omitting it returns diagnostics for all open files. Since schema coverage is 100%, and the description merely repeats the parameter's behavior, the baseline of 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 retrieves diagnostic messages for files, using a specific verb ('Get') and identifying the resource (diagnostics for files). It distinguishes itself from sibling tools like get_completions or get_code_actions by focusing on errors, warnings, and language-server-detected issues.

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 says 'Use this tool to identify problems in code files' and notes a prerequisite (files must be opened). It doesn't explicitly name exclusions or alternatives, but the clear scope provides sufficient guidance for when to use it.

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