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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering safety semantics. The description adds useful behavioral context beyond that: it clarifies that the document must have been 'previously attached to a calendar' and shows how to find acceptable doc_id values via get_status. This gives a concrete operational detail not present in annotations.

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, each with a clear purpose: the first states the action and scope, the second provides usage context and a pointer to find document IDs. There is no redundant phrasing or filler. It is front-loaded with the core verb and resource, making it easy to scan.

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 the tool's low complexity and the presence of annotations and an output schema, the description covers the essential context: what the tool reads, where IDs come from, and when to use it. It doesn't explain return values or error handling, but the output schema presumably covers that. The main gap is lack of context for calendar_id and admin_token, but those are inferable from the tool's purpose.

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 0%, so the description must compensate for the lack of parameter descriptions. It directly explains doc_id by saying 'ids are listed in get_status under documents,' which is helpful. However, it does not explain calendar_id or admin_token, leaving those parameters somewhat under-specified. The description partially compensates but not fully for all three required parameters.

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 function: 'Read a document previously attached to a calendar.' It distinguishes itself from siblings like attach_document, get_status, and revise_calendar by specifying its scope and resource. The reference to get_status for document IDs adds precise context, making it obvious this tool is for retrieving attached documents, not creating or modifying them.

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 provides explicit guidance on when to use the tool: 'Use when revising a plan so the new plan respects the syllabus/history the user provided.' It also points to get_status as the source for document IDs. Although it doesn't explicitly list alternatives or when-not-to-use scenarios, the use case is clear enough to guide an agent's decision-making.

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