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

Annotations cover safety flags, but with readOnlyHint=false on a nominal "read" the description usefully fills the gap by disclosing the paid nature (0.002500 test USDC on eip155:84532) and the retry/idempotency expectation. The payment cost and retry semantics are non-obvious behavioral facts that go beyond the 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?

Three short sentences with little padding, but the lead sentence is a tautology that consumes prime real-estate while the two genuinely informative facts (cost, retry) are pushed to the back. Not wasteful, but not front-loaded with purpose either.

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?

No output schema exists, so the description would need to convey the return value (the block hash for the given height), and it does not. Combined with the undocumented block-height parameter and the missing payment-flow detail, an agent lacks what it needs to call this confidently.

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 only 50% and the one undocumented parameter, the single-element `params` array, is left completely opaque — the description never says it is the block height. It adds only retry meaning for idempotencyKey, which the schema description already covers, so it fails to compensate for the gap.

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?

"Read getblockhash from Bitcoin" essentially restates the tool name plus the chain identifier; it never says the tool maps a block height to its hash. Crucially it does not distinguish itself from the nearly identical sibling bitcoin_getbestblockhash, so an agent cannot tell which to pick from the text alone.

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?

There is no when-to-use guidance and no mention of alternatives, even though bitcoin_getbestblockhash performs an obviously adjacent lookup. The only procedural note (preserve the idempotencyKey for retries) is a mechanical instruction, not selection guidance.

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