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

Annotations cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds genuinely new behavioral context beyond them: a one-market-day data lag, the fact that day states decay in minutes making the data stale by design, and a hard sample cap of 3 names plus 2 per cohort. These are exactly the traits an agent needs to avoid misusing the output.

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?

Three sentences, front-loaded with what the board contains and then the delay/sample caveats; every sentence carries information. It is dense with domain jargon (GO, FUEL, ROOM, lights grid) that is not unpacked, which slightly hurts immediate comprehension even though the payload reportedly includes a reading guide.

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, the description must convey the return shape, and it does: it lists the grid axes and per-name/cohort fields and states the sample size. It does not describe machine-readable structure or ordering, so an agent still has residual uncertainty about the exact response format, but the substantive content is covered.

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 there is nothing for the description to disambiguate; baseline for a no-parameter tool is 4. The description correctly introduces no parameter syntax that would conflict with 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?

The description names the resource (day-trade state map) and enumerates its concrete contents: per-name intraday lights grid across price/RSI/MACD timeframes, GO, FUEL vs anchor ETF, entry-window state and ROOM, cohort anchors, reading guide. It distinguishes itself from the closest sibling by explicitly framing itself as the 'delayed tier' versus a live feed, so an agent can separate it from get_day_board_live without opening either schema.

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 clear when-not-to-use guidance ('not a trading input', 'day states decay in minutes', delayed by one market day) and implies the correct use case: schema/shape preview. It stops short of naming the live alternative (get_day_board_live) explicitly, so routing is inferred rather than spelled out.

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