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

Annotations already declare readOnly, idempotent, and non-destructive behavior, but the description adds valuable context: the tool is 'live', and 'miner revenue is null when the source stops publishing it, never a misleading zero.' This discloses edge-case behavior directly and prevents misinterpretation of missing data.

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 all key facts front-loaded in the first sentence. It lists specific metrics concisely and adds one crucial edge-case note in the second sentence. Every word earns its place, and there is no redundant information.

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 tool has no parameters, an output schema exists, and the description enumerates the major fields returned, the information provided is complete for effective use. The description also adds the live nature and null-handling behavior, so there are no obvious gaps in understanding.

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, and the schema description coverage is 100%, so there are no parameter semantics to clarify. The description sensibly names the data fields returned, but for a no-param tool, the baseline of 4 is appropriate since there is nothing beyond the schema to explain.

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 resource ('Bitcoin network health') and provides a specific list of components (hashrate, difficulty, transaction count, estimated volume, miner revenue, largest recent mempool transactions). The instruction 'Call for on-chain Bitcoin activity' explicitly differentiates it from sibling tools like get_crypto_market or get_market_quotes, establishing a clear verb and scope.

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 phrase 'Call for on-chain Bitcoin activity' provides clear context for when to use this tool, implying it should be selected when on-chain metrics are needed rather than market or derivatives data. However, it does not explicitly name alternatives or state when not to use it, so it falls short of full explicit guidance.

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