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

Annotations already disclose readOnlyHint=true, destructiveHint=false, and idempotentHint=true, lowering the bar. The description adds useful context: it returns a step-by-step plan with cost/latency estimates and executable formats, and it restricts to 'public' tools. However, it doesn't go deeper into edge cases, such as pruning behavior or how it handles unavailable tools. It earns a solid 3 for adding some context without contradicting 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 two sentences: the first states the core action, the second details the return value and use case. It is front-loaded with the verb 'Compose' and includes no filler. Every sentence earns its place.

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 tool's moderate complexity (5 params, 1 required) and the presence of an output schema, the description provides a complete enough overview. It lists the key outputs (tool slug, endpoint URL, protocol, inputs, dependencies, costs, latency, executable plan) and mentions the supported protocols. It doesn't mention budget pruning defaults, but those are in the parameter descriptions. A 4 reflects that it is slightly incomplete for a planning tool but still sufficient.

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?

Input schema covers 100% of parameters with descriptions, so the baseline is 3. The tool description does not elaborate on individual parameters (goal, max_steps, budget_usd, etc.), but the schema already provides full semantics. The description adds no parameter-level detail beyond the schema, so a 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?

The description clearly states the tool's primary function: 'Compose a directed acyclic graph of public x402, MCP, and A2A tools that achieves a stated agent goal.' It specifies the resource (tools) and the action (compose a DAG), and distinguishes it from siblings by focusing on workflow composition rather than revenue, token strategy, or other single-purpose tools.

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 gives clear context: 'Useful for autonomous agents that need to pick which paid tools to chain.' This implies the tool's niche but doesn't explicitly mention when not to use it or name alternative tools. Since no exclusions are provided, it falls short of a 5 but is above a vague 3.

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