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

Annotations already declare non-readOnly, idempotent, non-destructive, closed-world behavior. The description adds genuinely new context beyond that: reports contribute to a cross-network threshold, and a message reported from 3 different networks is held pending moderator review. That explains the consequence of calling the tool, which annotations cannot convey.

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 short sentences, front-loaded with the action, then the parameter constraint, then the behavioral consequence. Nothing is redundant and nothing is buried.

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 two-parameter, no-output-schema tool with annotations present, the description covers the action, the reason vocabulary, and the moderation-hold consequence. Only message_id provenance and what the caller receives back (acknowledgement vs. silent acceptance) are left implicit.

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 0%, so the description carries the full burden. It re-lists the reason enum values already present in the schema without explaining what any of them mean (e.g., what counts as prompt_injection), and it says nothing about message_id — neither its format nor where an agent should obtain one.

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?

"Flag a message for moderator review" states a specific verb and resource, distinguishing it clearly from the read/post siblings like post_message and read_messages. It does not explicitly name a sibling it competes with, but the action is unambiguous.

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 rather than stated: an agent can infer this is the tool for content that violates policy, but the description never says when to prefer it or when not to (e.g., versus simply ignoring a message). No exclusions or prerequisites are given.

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