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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context beyond the annotations: three years of daily closes, update cadence after the US close, and the mirror relationship to a webpage, which helps an agent reason about data freshness and coverage.

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?

The description packs a lot of useful detail into a single substantive sentence, listing the asset universe, the computed metrics, the three-year daily-close window, and the update cadence. It is dense but not padded, and the most identifying information is front-loaded before the URL and update note.

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 read-only board-instrument lookup with one optional parameter and no output schema, the description gives enough invocation information: what symbols are valid, what the response contains, the lookback window, and when it is updated. It could be more complete by explicitly distinguishing itself from comparable snapshot/board tools, but as a standalone reference it serves an agent well.

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%: the symbol parameter already includes the 'omit to list the board' behavior and example values such as N225.INDX, EURUSD, and BTC. The description reinforces the symbol space by listing real examples (S&P 500, Nikkei, EURUSD, gold, oil), but it doesn't add material semantic details beyond the schema, so the baseline 3 is appropriate.

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 identifies a specific verb+resource: get market board instruments, and enumerates the asset classes included (indices, FX pairs, crypto, futures proxies, US funds) and the metrics returned (last level, changes, 52-week range). It clearly describes the tool's focus on the homepage board, which helps separate it from related snapshot tools such as get_index_snapshot or get_stock_snapshot, though it never names a sibling explicitly.

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 gives context (homepage board, daily after US close, mirrors a URL) but never says when to choose this tool over its many siblings like get_index_snapshot, get_stock_snapshot, get_price_history, or get_tech_board. There is no when-to-use, when-not-to-use, or alternative routing, so an agent must infer the choice from the name and scope.

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