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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the description does not need to re-state safety. It does add real value beyond them: result ordering (newest first), the scope restriction (this user's bookings only), and the presence of nextCursor for paging.

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?

One front-loaded sentence naming the resource, ordering, and return fields, followed by two short supporting clauses. 'Read-only' is redundant with readOnlyHint=true, a small wasted phrase, but overall it is tight.

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, the description correctly lists the returned fields and the cursor. However, for a two-parameter list tool whose main filter is tense, the absence of any explanation of upcoming vs past leaves the definition incomplete for correct invocation.

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 only 50%: cursor is documented in the schema, but the tense enum (upcoming/past) has no schema description and is never mentioned in the description either. The description therefore fails to compensate for the coverage gap on the tool's only meaningful filter.

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 concrete resource (the user's bookings taken by the call assistant) plus the returned fields (caller number, slot, booked/cancelled) and ordering (newest first). That is enough for an agent to tell this apart from list_calls or list_chats without opening a 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?

Usage is only implied by the resource name; there is no explicit 'use this when…' statement, no mention of the upcoming/past distinction, and no routing to alternatives such as list_scheduled_calls. An agent can infer the general case but not the boundaries.

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