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

Goes well beyond the readOnly/idempotent/openWorld annotations: declares statelessness, a 32 KB payload cap, 60 RPM rate limit, demo-mode bypass, L402 payment of 10 sats, and HTTP 400 on invalid input. These are operational facts an agent cannot infer from the annotations or schema.

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 sentences, front-loaded with purpose, then routing guidance, then operational constraints. Dense but every clause is functional; the parenthetical '(max 32 KB, 60 RPM)' is compressed rather than verbose, though the sentence is somewhat overloaded.

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?

Output schema exists so return shape needn't be described, and annotations cover the safety profile. Description fills the remaining gaps an agent needs: auth mechanics (L402/demo), rate/payload limits, error behavior, and sibling routing. Nothing material is missing.

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% and the sole parameter already documents the enum and the 'half_hour' default, so the schema carries the load. The description reinforces meaning by naming the tiers (fastest, half-hour, hour, economy) in the context of confirmation speed, adding slight framing value over the raw enum values.

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?

Names a specific verb (Fetches) and resource (Bitcoin mainnet mempool feerate recommendations) with the exact unit (sat/vB) and the four confirmation tiers enumerated. An agent can distinguish it immediately from estimate_solana_priority_fees and plan_bitcoin_utxo_consolidation.

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?

Explicitly states the use case ('before broadcasting an on-chain BTC transaction') and names the alternative with the condition that selects it ('for calculating exact SegWit/Taproot UTXO batch consolidation vByte weights and dust thresholds, use plan_bitcoin_utxo_consolidation instead'). Both when-to-use and when-not-to-use are covered.

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