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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds value beyond that by disclosing what the response contains — CoP in USD, spot, gross margin, above/below water, reference machine and tariff, and a 30-day trend where a reference-machine change 'indicates the efficiency frontier moved'. This is meaningful behavioral context, though it stops short of covering failure modes for untracked coins.

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?

Four sentences, front-loaded with the core definition, then the return payload, then usage guidance and alternatives. Dense with no filler, but the slight internal redundancy between 'gross margin' and 'whether miners are currently above or below water' keeps it just short of a perfect 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?

With no output schema present, the description correctly carries the return-value burden and enumerates every returned component, including the 30-day trend and the reference-machine-change flag. Both parameters are fully covered by the schema, annotations cover the safety profile, and sibling routing is explicit. An agent has everything needed to select and invoke the tool 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?

Schema description coverage is 100%, and both parameters are already richly documented: coin_id explains ambiguity rejection with shared-ticker examples (DGB, XVG, TARI), and electricity_cost_usd_kwh explains the 0.069 default, the residential-rate caveat, and its impact on conclusions. The description's 'Accepts a custom electricity rate' merely restates the schema, so the baseline 3 applies.

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: 'Cost of Production (CoP) for one Proof of Work coin' — the all-in electricity cost of mining one unit on the most efficient tracked hardware versus spot price. It is clearly differentiated from siblings by name ('use get_hardware_benchmarks' for a specific rig, 'calculate_solo_mining_odds' for block-finding probability), so an agent can distinguish it 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?

Explicitly enumerates the query intents this tool answers ('is mining X profitable', 'are miners underwater', 'break-even electricity price') and gives conditional exclusions with named alternatives: 'For a specific rig rather than a coin, use get_hardware_benchmarks. For block-finding probability, use calculate_solo_mining_odds.' Nothing is left to inference.

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