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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint false), so the bar is lower. The description adds useful context the annotations do not: that this reports state from 'our node' including local txindex sync status, which matters for deciding whether chain data is reliable. It does not describe pagination or freshness/refresh behavior, so it stops short of a 5.

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?

Front-loaded and sectioned (state list, when-to-use, do-not-use, returns), with the routing guidance placed early. The opening enumeration and the 'Returns:' enumeration largely restate the same field set, which is mild redundancy that keeps it from a 5.

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 must carry the return contract, and it does — it names the concrete return keys (difficulty, network_hashrate_hs, chain_tx_count_total, tx_rate_per_s, client, connections, relay_fee_btc_kvb, uptime_s, indexes{}). Combined with the explicit when/not-when guidance, an agent has everything needed to call it correctly.

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 takes zero parameters, so the baseline is 4 per the rubric. There is nothing parameter-specific the description could usefully add, and it correctly does not pad the schema with invented arguments.

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?

States a specific verb (get) and resource (Bitcoin network/node state) and enumerates exactly what fields it surfaces: difficulty, hashrate, tx counts, tx/s, protocol version, connections, relay fee, mempool size, uptime, and txindex sync state. This is clearly distinguishable from siblings like btc_get_block or btc_get_mempool_state without opening any schema.

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?

Explicit 'When to use' guidance (macro questions about hashrate, chain throughput, node index completeness) and explicit 'Do not use' routing to btc_get_fee_rates and btc_get_mempool_state. The condition that selects each alternative is named, leaving nothing to inference.

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