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

Annotations already cover the safety profile (readOnlyHint, non-destructive, closed-world), so the description's 'Read-only' restates rather than adds. It does add useful behavior detail beyond annotations: ordering (newest first), the hard 10-item cap, and the exact return shape (a displayTable Markdown table with named columns plus the same calls as data). It says nothing about pagination behavior or how cursor interacts with the cap.

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?

A single dense sentence that front-loads the core scope and return shape, with no filler. It is slightly over-packed, folding ordering, cap, output format, and alias rationale into one run-on line, but nothing 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, the description carries the burden of return values and does so concretely (table columns plus a data payload), which is the main thing an agent needs. The gaps are minor: no pagination explanation and no coverage of the callType filter, but a zero-required-parameter read tool needs little more.

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 67%: limit and cursor are documented in the schema, and the description only echoes the 10-item cap on limit. The callType parameter has an enum but no explanation in either the schema or the description, and the description never mentions filtering by call type or how cursor paging works.

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 resource (the user's recent calls) with scope qualifiers (newest first, up to 10) and explicitly equates itself to a named sibling (list_calls), so an agent can tell exactly what it retrieves and how it differs from other list_* tools.

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 context for selection by saying it is the same result as list_calls and is retained for apps already using this name, which implies new integrations should use list_calls. It stops short of an explicit 'prefer list_calls' instruction or exclusions relative to siblings like get_call or search_contacts.

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