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

The annotations only declare the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds operational behavior beyond that: 32 KB max payload, 60 RPM rate limit, statelessness, the two settlement paths ('?demo=true' vs MPP for 100 sats), and failure behavior (HTTP 400 on invalid input). These are exactly the execution traits an agent needs before calling.

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 three tight sentences that lead with purpose, then routing, then operational limits, and nothing is buried. The '?demo=true' query-string notation is slightly out of place in a tool whose schema is a JSON object, which is a minor structure wobble.

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?

An output schema exists, so the return shape need not be spelled out, and the description still gives a useful summary ('step-by-step execution plan'). Payment, limits, and error modes are all covered; only the wrong default value keeps this from being fully complete.

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 100%, so the baseline would be 3, but the description actively contradicts the schema: it says token_quota_tier 'defaults to compact_1024' while the schema documents a default of 'standard_4096'. An agent trusting the prose would allocate the wrong quota tier. The description adds no other parameter meaning beyond restating the field names.

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 names a specific verb and resource: it 'Initializes a Base USDC Machine Payments Protocol (MPP) metered inference session, allocating a streaming token quota and returning a step-by-step execution plan.' It also distinguishes itself from the nearest sibling by naming route_mcp_workflow_plan as the tool for the case where no MPP session is opened.

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?

It states the condition that selects this tool ('Use when running session-metered agent planning settled via Base EVM MPP Payment-Challenge headers') and states the condition that selects the alternative ('for mapping a task goal to L402 MCP tool calls without opening an MPP streaming session, use route_mcp_workflow_plan instead'). Both the when and the when-not are explicit.

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