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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower, but the description still adds real value by disclosing ordering and explicit exclusions: no recordings or transcripts, and it never places a call. It stops short of mentioning pagination or result-count behavior beyond the limit default.

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?

Two tight clauses: the content/ordering claim is front-loaded, followed by the safety/scope disclaimer. Every phrase carries information; nothing is repeated from the schema or annotations.

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 an output schema present, the description needn't explain return values, and annotations cover safety. What remains — ordering, scope exclusions, and field content — is covered; only filter-combination guidance and pagination behavior are absent, which is minor for a simple filtered list.

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 100% — limit bounds, ISO 8601 format, direction enum, and contact uuid are all documented in the schema. The description adds no filter syntax or edge-case semantics (e.g., invalid since values, filter combination behavior), so the baseline 3 applies.

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 the specific resource (the Mighty Dial call log) and enumerates the returned fields — direction, from/to numbers, status, duration, voicemail flag, matched contact — plus ordering (newest first). No sibling tool lists calls, so the agent can place it immediately.

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 implied: this is the tool for reviewing call history. However, there is no explicit when-to-use/when-not, no mention of alternatives (e.g., get_contact for a single contact's context), and no guidance on combining filters such as since+direction.

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