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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered; the description adds genuinely new context: it is unauthenticated, and new-coin plus XP hashRate/blockReward values 'may be null/omitted', which warns the agent about sparse fields. It does not describe payload size, caching, or freshness, keeping it below 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?

A single front-loaded sentence opens with the endpoint and resource, then adds the differentiating and caveat clauses. The long ticker list is slightly bloated but arguably earns its place by setting expectations about coverage.

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 and no parameters, the description carries the burden of describing the return payload, and it does so in outline (prices plus network hashrate/difficulty) with the null-field caveat. A hint at the response shape or field nesting would push it to 5.

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 of 4 applies; there is nothing for the description to disambiguate. The coin enumeration is descriptive flavor rather than 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 the exact endpoint and resource ('GET /api/v1/market-data — public full market payload') and enumerates the coin coverage plus the extra hashrate/difficulty fields. It also explicitly contrasts with the sibling get_market ('Broader than get_market'), so an agent can distinguish the two without opening schemas.

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?

The phrase 'Broader than get_market' gives clear selection context against the obvious alternative, and 'No API key required' signals it is freely callable. It stops short of an explicit when-to-use/when-not rule (e.g. 'use get_market for prices only'), so it is strong but not complete.

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