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

Annotations declare readOnlyHint and non-destructive, so the safety profile is covered. The description adds valuable domain-specific behavior: oldest-first ordering, limit of last 100, the meaning of 'unread' status for both owner messages and unanswered agent questions, and that owner messages are consumed on next wake. This is rich context beyond annotations, though it doesn't detail pagination or return format.

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 dense sentences that front-load the core definition. It is appropriately sized for the domain complexity, though some allocation of detail could be slightly tighter.

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?

Given a single parameter, readOnly annotations, and no output schema, the description covers the essential semantics of the inbox and its lifecycle. It omits some minor details like pagination or error cases, but is largely complete for safe invocation.

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 0% for the single parameter influencerId, but the parameter name is self-explanatory and its type/format is defined in the schema. The description doesn't add syntax or meaning beyond what the name implies. With one parameter and no output schema, baseline 3 is appropriate.

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 ('the two-way owner ↔ agent inbox for one influencer') with precise scope. It is clearly distinguishable from sibling send_influencer_message and other influencer tools by naming the inbox context.

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?

Explains the purpose of reading the inbox and routes the agent to the alternative for a related action ('answer them via send_influencer_message with answerToMessageId'). However, it doesn't explicitly state when-not to use this tool vs other read tools, so it's not a full 5.

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