Get Open Counts

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

Annotations already declare readOnlyHint and idempotentHint, so the description need not restate those. It adds the key behavioral prerequisite that open tracking must be enabled, and clarifies that the count refers to recipients (implying unique recipients), which is useful context beyond the annotations.

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?

The description is a single sentence of 14 words, front-loaded with the core action and resource, and immediately states the key requirement. Every word earns its place; no wasted text or repetition of schema details.

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-only count tool with an output schema and annotations, the description covers the essential purpose and prerequisite. It does not elaborate on filtering or return details, but the output schema can handle that, so the description is sufficiently complete within its context.

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 50% (fromdate and todate have descriptions, but tag and messagestream do not). The description provides no additional parameter meaning, failing to compensate for the undocumented parameters or explain how filters like tag or messagestream affect the counts.

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?

The description uses a specific verb 'Get counts' and a clear resource 'recipients who opened emails', which precisely identifies the tool's function. It distinguishes from sibling tools like get_click_counts and get_sent_counts by specifying 'opened emails'.

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?

The description implies usage for retrieving open counts and mentions the prerequisite 'requires open tracking', but it does not explicitly state when to use this tool over alternatives or provide exclusions. It lacks direct comparison with sibling count tools such as get_click_counts.

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