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

Annotations already declare readOnly, idempotent, non-destructive, open-world, but the description goes well beyond them: 1-hour result caching with <5ms hits, $0.01/call pricing, first 5 calls free, failed calls never charged, and the crucial non-fatal payment-required quote behavior with a retry path. This is exactly the kind of operational context annotations cannot express.

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?

Front-loaded with purpose, then when-to-use, then parameter interactions and pricing, and it includes a concrete example call. It is dense and mostly earns its length, though the pricing details are restated ('$0.01 per call' followed by a fuller 'Pricing:' block), which is mild redundancy.

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 return values need not be explained, and the description covers the remaining gaps an agent needs: cost, trial limits, caching, and the exact recovery flow after a payment-required response. Complete for a paid, stateful polling tool.

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 is 3, but the description adds the cross-parameter interaction the schema only implies per-field: omit both agent_id and tx_hash during the 5 free trial calls, then supply either an agd_pass_ key or a tx_hash for paid execution. It adds real routing value, though some of it overlaps the per-parameter schema text.

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 (stateful 5-minute delta feed computing DEX buy/sell ratio, DeFiLlama APY spreads, Polymarket odds) rather than restating the name. It also names the sibling get_agent_wallet_status and what that sibling is for, so an agent can route without opening either schema.

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?

Explicit WHEN TO USE and WHEN NOT TO USE sections, including the exact trigger condition ('task requires deterministic alpha-stream analysis for target'), the alternative tool for quota checks, and the exclusion ('unrelated domains or binary media'). Nothing is left to inference.

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