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

With no annotations, the description carries the full burden of behavioral disclosure. It indicates an action ('attach') that implies mutation but does not explain effects, reversibility, permissions, or failure behavior. It only mentions signature requirements, which is a partial disclosure. Significant behavioral gaps remain.

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 brief (two sentences) and front-loads the core action. It avoids fluff, though the phrasing 'the watcher has not matched on its own' is slightly convoluted. It earns a high score for economy, but loses a point for clarity of structure.

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?

For a mutation tool with no annotations, no output schema, and 0% schema coverage, the description is inadequate. It does not cover return values, errors, preconditions, or the meaning of 'terms' beyond a pointer. An agent would need to consult external docs to use it correctly. The description leaves major gaps in operational context.

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 description coverage is 0%, so the description must compensate for undocumented parameters. It does not explain what 'id' and 'txHash' represent, nor the role of 'signature' beyond referencing terms. The mention of 'attach a transaction' hints at txHash being a transaction hash and id being an invoice identifier, but this is not explicit. For a 3-parameter tool, the description adds minimal semantic value.

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 states a specific action (attach a transaction to an invoice) and the condition (the watcher has not matched it). It clearly conveys the tool's purpose and differentiates from likely siblings like mint_invoice, though it does not explicitly name alternatives. The term 'watcher' is jargon but not fatal.

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 provides some usage context by referencing the terms (payment.sentADifferentAmount) that dictate when a signature is required, but it does not explicitly state when to use this tool versus alternatives (e.g., when the watcher has matched a transaction). The guidance is implicit and relies on external terminology.

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