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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds real value by disclosing the report's contents (counts, per-link clicks, domain distribution) and the conditional nature of A/B and social sections, though it says nothing about auth requirements or behavior when a report_id does not exist.

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?

Three compact clauses front-load the core purpose and then enumerate contents and optional sections; the endpoint is tacked on as a single useful token. No filler or redundancy.

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 no output schema, the description carries the burden of describing return values, and it does so concretely: delivery and engagement counts, per-link click counts, recipient domain distribution, plus optional A/B and social stats. Minor gaps remain around error handling and the `fields` projection effect, but the essentials are present.

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 coverage is 75%, so the two boolean flags and the `fields` projection are already documented in the schema. The description only restates that A/B and social statistics are optional inclusions and does not explain `fields` projection semantics or report_id format/preconditions, so it adds little beyond structured data.

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 and resource ('one send report by id') plus the payload it returns: delivery/engagement counts, per-link clicks, and recipient domain distribution. This clearly distinguishes it from vision6_list_reports, which enumerates reports rather than fetching a single one.

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 by 'by id' — you call it when you already have a report_id and want the detail view — but the description never says when to prefer vision6_list_reports or when to set the optional include flags. No exclusions or preconditions are given.

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