Index history

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

Discloses a non-obvious behavioral constraint absent from the schema: results are returned "oldest first" and capped at "at most 60 evenly spaced points." That downsampling behavior directly changes how an agent should interpret `days` (a 4000-day request still yields 60 points), and it adds that the series carries the window's change. Annotations already cover the safety profile, so this is pure added value.

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?

Two sentences, no filler: mechanics first, then when-to-use with quoted example questions. The most surprising fact (60-point cap) sits in the opening sentence where it cannot be missed.

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 still manages to convey ordering, granularity, result volume, and that the value series includes window change — enough to use the tool correctly. Return field shapes (low/high, rolling returns) are only in the schema descriptions, so not everything is covered, but the critical gaps are closed.

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% and each parameter already has a meaningful description, so the schema does the heavy lifting. The description's "evenly spaced points" and "over the window" hints loosely connect to `days` and `series` but add no format or interpretation detail beyond what the schema states. Baseline 3 applies.

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?

States a specific verb and resource ("get the daily history of one market or industry index") with scope qualifiers (single index, daily granularity, oldest first). It also implicitly distinguishes itself from fp_history (fund history) and positions fp_indices as the lookup step, so an agent can pick it without opening the 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?

Explicitly prescribes the workflow ("Use after fp_indices") and gives two concrete motivating questions ("how did the bourse index move this year", industry vs fund market comparison). No exclusion statement — it never says to use fp_history instead for funds — but the context is clear.

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