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

Annotations already provide readOnlyHint=true and destructiveHint=false, but the description adds critical behavioral context: the tool never sends a webhook, never accepts a destination, and produces 'bounded deterministic' output. The pricing note ($0.05/call, x402) is an additional transparency element. This goes beyond what annotations alone 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?

The description is exactly two sentences: the first densely packs purpose, scope, and target selection; the second states a vital safety guarantee. No repetitive or unnecessary wording, and it is well front-loaded.

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 the complexity of nested inputs and 4 parameters, the schema thoroughly documents all inputs and constraints. The description covers purpose, safety, and pricing. Since there is no output schema, the description could have clarified return-value structure, but the tool name and purpose make it obvious that it returns the built payload. The overall definition is complete enough.

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?

The input schema provides 100% description coverage with detailed field descriptions, enums, nested item schemas, and constraints (e.g., maxLength, patterns, min/maxItems). The description itself adds no parameter-specific information, but the schema already carries that burden. Baseline 3 applies due to high schema coverage.

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 states a specific action ('Build one bounded deterministic unsent payload') with clear targets (Slack, Teams, generic webhook) and input source ('normalized signal and buyer-supplied evidence'). It distinguishes from siblings by explicitly noting 'The Actor never sends a webhook or accepts a destination,' which differentiates it from any potential sending or destination-consuming tool.

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 conveys when to use the tool: to construct a payload for Slack/Teams/generic from a normalized signal and evidence. It also provides an exclusion by stating 'never sends a webhook or accepts a destination,' which signals when not to use it (if delivery is needed). However, it does not name specific alternative tools, so it falls short of fully explicit guidance.

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