sign_btc_multisig_psbt

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

Annotations indicate destructiveHint=true and idempotentHint=true. The description adds security-critical behavior: validates bip32_derivation on inputs, requires on-device output walkthrough matching chat-side verification, and returns partial PSBT without broadcasting. It does not explicitly state that the operation modifies the PSBT (adding signatures), but this is implied. No contradiction with 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 informative but slightly verbose (multiple sentences). However, it is front-loaded with the core purpose and each sentence serves a purpose (security, user steps, limitations). Could be tightened but remains effective.

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 multi-sig signing, the description covers prerequisites, security checks, user workflow, return value (partial PSBT), and what the tool does not do (finalize/broadcast). No output schema exists, but the return is adequately described. Complete for an agent to use correctly.

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 covers both parameters (100% coverage). Description enriches meaning: walletName clarified as a previously registered name, psbtBase64 includes size cap (200KB), validation rules (bip32_derivation check), and user verification steps. This adds significant context beyond the schema.

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 identifies this as a co-signer flow for multi-sig PSBTs, specifying the verb 'sign' and the resource 'btc_multisig_psbt'. It distinguishes from sibling tools like combine_btc_psbts and finalize_btc_psbt by stating it adds a Ledger signature to an externally initiated PSBT.

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 when to use (co-signing a multi-sig PSBT from initiators like Sparrow/Specter/Caravan) and when not to (does not finalize or broadcast). Mentions prerequisite wallet registration via register_btc_multisig_wallet and advises that the initiator handles final steps once all M signatures are collected.

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