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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the '[read]' prefix is redundant. The description adds merchant scoping, which is useful, but omits the refresh parameter's caching semantics and how null dates are treated — meaningful behavioral gaps for a data-fetching tool.

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, front-loaded with the verb and resource, and the scoping details follow logically. The only wasted token is the redundant '[read]' tag.

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 5-parameter tool with no output schema and no per-parameter schema descriptions, the definition covers identifiers and dates but leaves refresh behavior, defaults, and the report's return shape unexplained. It is enough to attempt a call, but not enough to call it confidently.

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?

With 0% schema description coverage the description must compensate, and it partially does: it clarifies that metric_account_id and metric_account_uuid are alternatives and gives the YYYY-MM-DD date format plus inclusive range semantics. It says nothing about the refresh flag, default values, or which parameters are optional.

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 verb (Fetch), resource (analytics report) and scope (one metric account, date range, caller's merchant), which is clearer than the bare 'Get Metric Report' title. It does not distinguish itself from sibling report tools such as get_website_report or get_utm_sources_report, so an agent must infer the difference.

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 only implied: the description signals you need a metric account identifier and a date range, but it never says when to prefer this over related report tools or that metric_account_id can be obtained from list_metric_accounts. No exclusions or prerequisites are stated.

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