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

Annotations already declare readOnlyHint=true, so the agent knows it is a safe read. The description adds that calls are scoped to the account and returned newest-first, which is useful context. It does not disclose anything about pagination or response shape, but for a read-only list the annotation covers the core safety profile.

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 entire description is one sentence with the verb and object front-loaded. The parenthetical 'most recent first' adds necessary ordering detail without fluff. There is no waste.

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 simple read-only list tool with one optional parameter, the description covers the core (what is listed, whose, and the order). The lack of an output schema means an agent won't know the exact return fields, but that is a minor gap given the straightforward nature of the tool and the existing annotations.

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 single parameter 'limit' is fully described in the schema (integer, max 100, default 20). The description adds nothing about it, and with 100% schema coverage the baseline of 3 applies. No additional meaning is needed.

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 (List), resource (recent calls), scope (placed by your account), and ordering (most recent first). This clearly distinguishes it from get_call (single call lookup), place_call (new call), and set_appointment (appointments) without needing to open the schemas.

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 implies usage: it is for viewing your own recent call history. However, it does not explicitly state when to use it over get_call (e.g., 'for a single call, use get_call') or provide any exclusions. The boundary is inferable from names but not stated.

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