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

With annotations covering the safety profile, the description still adds substantial behavioral context beyond them: null readings are not zero, partial flow subtotals are not complete totals, next_cursor signals incomplete upstream history, and OI lines must use nested matching-cycle venues rather than local sums. These directly affect how an agent interprets and trusts returned data.

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-loaded with the usage trigger, then organized under Selection/Presentation/Evidence headers, so it is scannable despite its length. A few lines (e.g., 'Pattern events have no widget') are niche, but overall the sentences carry information rather than filler.

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, the description need not explain return shape; instead it covers selection defaults, evidence reading, cursor semantics, and data caveats. An agent has everything needed to invoke and correctly interpret this tool.

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 baseline is 3, but the description adds cross-parameter defaulting rules not obvious from the schema alone (indicators default to calculation=candles at 1h/4h/1d with exact variant ID; numeric snapshot/flow families default to alignment=candles; native is never a fallback). Some of this duplicates the schema text, capping it below 5.

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 action (read one metric/study/source rows as a paginated series) and explicitly carves out what it is not for (research_interpret_range, invented indicators, replay frames). It is clear but does not differentiate itself from the many display siblings (research_show_funding, research_show_price), leaving the agent to infer the raw-series vs widget distinction.

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?

It gives an explicit 'use when' trigger, an explicit 'do not use' list naming a sibling alternative, and concrete routing rules ('Use facts.display_tool for its focused widget'). Follow-up preservation and cursor-following guidance make the conditions of use unambiguous.

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