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

Annotations only declare read-only/open-world safety; the description adds substantial behavior: ranking order (importance then recency), the importance scale (0-10, 8+ = market-moving), the ageMinutes field, the scoring-lag caveat that an empty list does not imply no news, and an auth requirement (API key with read scope). This is behavior an agent could not infer from 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?

Front-loads purpose in the first clause, then layers return semantics, the scoring-lag caveat, and the auth requirement. Every sentence carries non-redundant information; nothing is padding.

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?

Despite five parameters including a nested agentTrace object, the 100%-covered schema plus an output schema carry the structural detail, and the description handles the operational caveats (lag, auth, ranking). 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?

Schema description coverage is 100%, so the schema already documents coins, hours, limit, minImportance, and the agentTrace object. The description reinforces meaning ('up to 25 coins', importance 0-10) and implicitly informs minImportance via the '8+ = market-moving' guidance, but adds little syntax beyond what the schema states, 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 ('Recent crypto news for up to 25 coins') plus the linking mechanism ('CoinRithm's curated coin-news graph'), so an agent knows exactly what comes back. No sibling tool returns news, and the scope is explicit enough to distinguish it from market-data siblings like get_market_context.

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?

Usage is implied rather than stated: it is clearly for fetching coin-linked news, and the tool notes the 'up to 25 coins' and 'only AI-scored stories' constraints. But it never says when to prefer this over gathering news elsewhere, nor does it name any alternative or prerequisite workflow.

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