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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering safety. The description adds valuable nuance: 'Miner revenue is null when the source stops publishing it, never a misleading zero,' which explains a potential output edge case. This goes beyond the annotation baseline, but does not exhaustively describe all behaviors (e.g., throttling or data freshness). A 4 is appropriate.

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 two sentences with no fluff. The main purpose is front-loaded, and the additional note about null values is essential and efficient. Every word earns its place, fitting the conciseness ideal.

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 zero-parameter, read-only tool with an output schema, the description fully covers what the tool does, what it returns, and a key behavioral nuance (null handling). There are no missing prerequisites, side effects, or return format ambiguities. The description is complete for the tool's complexity.

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?

The tool has zero parameters, so the baseline for parameter semantics is 4 per the rubric. The description does not need to explain parameters since none exist, and the schema coverage is moot. The description's mention of what data is returned (e.g., 'largest recent mempool transactions >10 BTC') indirectly informs what the output contains, which is sufficient.

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 states the tool's purpose: 'Live Bitcoin network health' and lists specific metrics (hashrate, difficulty, transaction count, etc.), distinguishing it from sibling cryptocurrency tools like market quotes or news. The verb 'get' and resource 'BTC network' are explicit, and the scope is unambiguous.

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 'Call for on-chain Bitcoin activity,' which gives a clear use case. It does not explicitly mention when not to use it or alternatives, but given the sibling list, the context is enough to infer this is for network health rather than market data. Lacking explicit exclusions, it earns a 4 rather than a 5.

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