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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so the safety profile is covered. The description adds meaningful behavioral context beyond that: the (date, value) point shape, the hard 400-point cap, per-chart units (LAX, gwei), and the 'approximate' marker for in-progress periods. These are real operational traits not present in the structured fields.

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 core behavior and the network_trends routing are front-loaded, and the long chart enumeration earns its place because it substitutes for missing enum values. It is dense but not padded; slightly heavy as a single run-on block of clauses.

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 return-shape burden and does so: (date, value) points, resolution granularity, date range defaults, the 400-point cap, and unit reporting. An agent has everything needed to call this correctly and interpret results.

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 100%, so the baseline is 3, but the description genuinely enriches the parameters: it enumerates all valid chart ids by section, defaults for from/to (last 90 points), and notes DAY as the default resolution. The enumerated chart list is valuable since the schema declares no enums for these fields.

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 ('Time series from the explorer's statistics service') and clearly distinguishes two modes: listing available charts when 'chart' is omitted vs. returning points when it is supplied. The explicit routing to network_trends for hashrate/difficulty/block time/node counts further separates it from siblings.

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?

Gives explicit when/when-not guidance: omit 'chart' to enumerate charts, supply 'chart' to fetch a series, and use network_trends instead for the last 7 days of hashrate, difficulty, block time and node counts. The alternative and the condition selecting it are both named.

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