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

No annotations are provided, so the description carries the full burden — and it does substantial work: it warns that the body can be hundreds of KB per document and is omitted by default, explains the focused-first ordering, and flags that `durable_document_id` is null until the first save. It does not cover auth requirements or rate/refresh caveats.

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?

Front-loads the core behavior in the first sentence and uses a labeled ID MAPPING block to organize the denser id-semantics content. Some of the mapping prose is verbose (multiple sibling names in a single clause), but no sentence is wasted.

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?

With no output schema and no annotations, the description must describe returns itself — and it does, listing id, chunk count, focused flag, and changed_since_seen. The inclusion of the id-mapping rules is essential context that a bare schema would hide, though session_id semantics and error behavior remain unaddressed.

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 50%: `include_html` and `report_changed` are already well documented in the schema, while `session_id` and `authorization` are undocumented in both places. The description reinforces when to set include_html=true but adds no syntax or constraints for the required `session_id`, so it only partially compensates.

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?

States a specific verb+resource+scope: returns the editable documents open in *this session*, focused first, with named fields. It also explicitly distinguishes itself from `list_documents` (Files) via the ID MAPPING section, so an agent can tell session-scoped from durable-document listing without opening either schema.

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?

Gives clear context for use (render document tabs; enumerate/switch tabs token-light) and names the alternative form of the id accepted by `focus_session_document`, `close_session_document`, and `chat`. It does not explicitly state when *not* to use this versus `list_documents`, but the id mapping effectively routes the agent between them.

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