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

No annotations are provided, so the description carries the burden. It discloses that the tool handles both confirmed and unconfirmed transactions and returns a summary, which is useful. However, it does not disclose behavior like whether the txid must be lowercase, whether it queries a local node or external API, rate limits, or error behavior for unknown txids. The description is honest but not deeply transparent.

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?

Two sentences, front-loaded with the core purpose and return fields, followed by a crisp usage rule and exclusion. Every sentence earns its place; no filler or repetition of schema details.

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 single-parameter lookup tool with no output schema, the description covers the input format, the use case, and the sibling distinction. It could mention what happens for an unknown or invalid txid, but the schema pattern already enforces format, and the tool's scope is narrow. Slightly more behavioral detail would make it complete, but it is largely sufficient.

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%: the txid parameter is fully described in the schema with pattern and description. The description adds the context that the txid is a 64-hex BTC txid, but that's already in the schema. No additional parameter semantics are needed beyond what the schema provides, so baseline 3 is appropriate.

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 verb ('Look up') and resource ('Bitcoin transaction by txid'), and enumerates the exact data points returned (confirmation status, block height, confirmations, size, input/output summary). It also distinguishes itself from sibling tools by naming chain_status as the alternative for other chains.

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 explicitly says when to use this tool: when the user gives a 64-hex BTC txid and asks whether it confirmed or which block it is in. It also gives a clear exclusion: do not use for other chains, use chain_status instead. This is explicit when/when-not guidance.

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