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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the bar is low. The description adds meaningful behavior: it is a data aggregator with real-time Tavily search plus internal event pool, returns data-completeness status, 'No account access, no order placement or fund transfers,' and 'Not investment advice.' These disclose boundaries beyond the annotations. No contradiction; the 'Read-only' claim aligns with readOnlyHint=true.

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?

Roughly four sentences with the core purpose front-loaded, followed by role clarification ('data aggregator... downstream agent performs final attribution'), then safety disclaimers. Every sentence earns its place; the '[Read]' prefix is slightly redundant with readOnlyHint but harmless. Efficient and well-ordered.

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 an output schema present and safety annotations covering read/order/account boundaries, the description covers the essential operational facts: data sources, aggregator role, completeness status, and the non-advice caveat. The only notable gap is no explicit distinction from get_market_move_report/list_market_move_reports, but for a read-only aggregator with a rich output schema this is largely complete.

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%, with each parameter (coin, lang, mode, query, time_range) well-documented in the schema including defaults and example values. The description does not add parameter-specific meaning beyond the schema — it only contextualizes the return structure. Per the calibration baseline, 3 is appropriate when the schema carries the load.

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?

The description states a specific verb+resource: 'Explain what drove a crypto asset's price move in a given time window.' It clarifies its role as a data aggregator whose downstream agent performs attribution reasoning, which loosely distinguishes it from report-generating siblings like news_events_get_market_move_report. However, it never explicitly names a sibling to contrast with, and the verb 'Explain' slightly conflicts with the disclosure that the tool only aggregates data rather than producing the explanation. Clear but not fully differentiated.

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 description implies when to use it ('Explain what drove a crypto asset's price move') and describes its output (summary, high-priority events, event pool items, completeness status). Yet it offers no explicit exclusions or named alternatives among the many news_events_/news_feed_/news_prediction_ siblings, leaving an agent to infer the boundary between this aggregator and get_market_move_report or web_search. Usable context, but no routing guidance.

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