document_open

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

With no annotations, the description carries the behavioral burden well: it discloses the active-document side effect, the already-open activation behavior, the `already_open` flag, and the accepted input types. It does not cover permission/auth requirements or what happens to an unsaved current document, which keeps it below the top score.

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 front-loaded with the core action, then adds the key constraint, already-open behavior, return note, and examples. Every part earns its place and the examples are compact.

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 two-parameter tool with no annotations and no output schema, the description is nearly complete: it explains inputs, side effects, and return values. The main remaining gap is explicit comparison to sibling tools such as document_activate and document_new.

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 already 100%, so the baseline is 3. The description adds meaningful semantics beyond the schema by requiring exactly one of the two parameters and clarifying that `local_path` must be an existing local `.f3d` file.

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 states a specific verb and resource: "Open a document and make it active." It distinguishes cloud files from local .f3d files and explains the already-open case, which helps separate it from document_activate and document_list.

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 gives clear usage constraints: pass exactly one of `file_id` or `local_path`, and other formats such as STEP are not opened here. It does not explicitly name document_activate or document_new as alternatives, so it falls short of fully explicit routing guidance.

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