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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely non-obvious behavior: without lead_id the result is scoped to calls *you* logged, not all calls, and the window is the last N days. It omits ordering and the limit/pagination behavior.

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 sentence that front-loads the primary mode and conditions the fallback mode. No filler, no restatement of the title, every clause carries information.

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 tool with no output schema, the scoping semantics are covered, but limit, result ordering, and return shape are absent while all three parameters sit at 0% schema description coverage. Adequate but with visible gaps.

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 0%, so the description must carry parameter meaning. It conveys the role of lead_id and days ('last N days') but never mentions the limit parameter at all, and adds no format, range, or default detail beyond what the schema already encodes.

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 (logged calls) and two precise scopes: calls on a given lead, or the caller's own calls within a day window. This clearly separates it from write-side siblings like log_call, though it never names an alternative explicitly.

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?

Gives the branch condition that selects each mode ('if no lead is given'), which is real routing guidance an agent can act on. It stops short of stating when not to use the tool or pointing to siblings such as lead_details or my_follow_ups.

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