open_document

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

With no annotations provided, the description shoulders the burden of behavioral disclosure. It does reveal a key behavioral trait—'The file remains open for continued analysis until explicitly closed'—which is useful. However, it omits other details such as error handling (e.g., if the file path does not exist) or whether reopening a file has any side effects, so the transparency is moderate.

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 two sentences, front-loaded with the primary action, and every clause earns its place. It packs the core purpose, usage timing, and persistence behavior without redundancy or excessive detail.

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 description sufficiently covers the tool's role, use case, and lifecycle for a simple open operation. It does not detail return values, but there is no output schema and the tool likely returns nothing important. Given the simplicity and strong schema coverage, the only missing elements are edge-case behaviors, which do not heavily detract.

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 input schema already provides descriptions for both parameters (file_path and language_id), covering 100% of parameters. The tool description adds no extra parameter-level detail beyond their purpose in the overall workflow, so the baseline score of 3 is appropriate given the schema's thorough coverage.

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 action ('Open a file in the LSP server') and its purpose ('for analysis'). It distinguishes from sibling tools like close_document and get_diagnostics by framing it as a prerequisite step, making its role unambiguous.

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?

It explicitly says 'Use this tool before performing operations like getting diagnostics, hover information, or completions for a file,' providing direct guidance on when to invoke it. It also notes the file remains open until explicitly closed, implicitly suggesting the companion tool close_document for cleanup, though it does not name an explicit alternative.

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