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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is fully carried by structured data. The description adds useful context about the time window semantics and the 'sending ramp today' metric, but says nothing about freshness, caching, or how partial days are handled. Adequate but not rich.

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 front-loaded sentence with no filler; the parenthetical for the day range is compact. Nothing is wasted, though the enumeration of metrics runs slightly long.

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?

An output schema exists, so return values need not be explained, and annotations cover the safety profile. For a simple read-only stats lookup with full schema coverage, the description is complete enough, with the only real gap being sibling differentiation.

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% with only 2 parameters, so the baseline is 3. The description restates the days range and default (already in the schema) and hints at the tenant identifier semantics already documented in the schema, adding no new meaning.

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?

It names a specific resource (a tenant's stats) and enumerates the metrics returned: email counts, bounce rate, complaint rate, and today's sending ramp. That is far clearer than a tautological restatement, though it never explicitly distinguishes itself from the nearby get_tenant or get_deliverability siblings.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives. An agent cannot tell from the description why it would call get_tenant_stats rather than get_tenant or get_deliverability for similar questions.

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