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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false, so the safety profile is covered. The description adds genuine boundary disclosure the annotations do not — that this service does not index Zcash transactions or wallets — which prevents inappropriate expectations of address-level data. It stops short of disclosing freshness assumptions beyond 'whether the node is caught up', but is solid for a read-only snapshot.

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-loads the one-line purpose, then layers use/don't-use and returns in a predictable order with zero filler. The 'Returns:' inventory is long, but it earns its place because no output schema exists — a slight density cost rather than waste.

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?

With no output schema, the description carries the full burden of describing the response and does so precisely: blocks/headers/estimated_height/chain_supply/difficulty/size_on_disk_gb, node_value_pools, a pools[] array with pool, balance, share_of_supply_pct, delta_1h, delta_24h, plus shielded_total and shielded_pct. Combined with the read-only annotations and zero-param schema, an agent has everything needed to call and interpret it.

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 and there is no parameter meaning to add or omit. The description correctly spends its budget elsewhere rather than fabricating parameter guidance.

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 and resource — 'Zcash chain state plus the distribution of all six value pools' — and names the distinct scope ('six value pools') that separates it from siblings like zec_get_network_stats and zec_get_treestate. The addendum 'in one call' also signals this is a composite snapshot rather than a single-metric probe.

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?

Explicitly structured as 'When to use' (shielded pool balances, shielded share of supply, node sync state) and 'Do not use' (no transaction or wallet indexing), with a named alternative — 'for node peers and disk usage call chain_status'. Both the positive trigger and the exclusion/routing are spelled out, 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.