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

Annotations already carry the safety profile (readOnly, idempotent, non-destructive, open-world), so the bar is lower. The description adds genuine value by listing the returned aggregates and calling out the 'underlying snapshot timestamp', which matters because there is no output schema. It stops short of stating data freshness or rate limits.

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 sentence, front-loaded with the verb and scope, with the returned fields as a compact list. Nothing is redundant with the title beyond the necessary scope word.

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?

For a no-param, no-output-schema tool, the description covers both what is fetched and what comes back, which is the main gap an agent faces. It omits freshness/update cadence and any hint on when the global view should precede per-asset calls.

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 no parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The enumeration of what the snapshot contains compensates for the empty schema.

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?

Specific verb (get) plus a well-scoped resource: current global cryptocurrency market aggregates, with the returned metrics enumerated. The word 'cryptocurrency' implicitly separates it from get_macro_snapshot, but the description never names that sibling, so an agent must infer the boundary.

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?

No explicit when-to-use, when-not-to-use, or alternative is given. For a zero-parameter global-overview tool the intended usage (market-wide context versus per-asset calls like get_asset_quote) is strongly implied but left to inference.

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