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

With no annotations, the description carries the full behavioral burden. It discloses key traits: missing hours represent missed passes (never zero), settled hours are immutable (no freshness gate), future-dated buckets are refused, and ordering is newest first. This is substantial behavioral context beyond the schema. Lacks only explicit confirmation of the returned data shape but is strong otherwise.

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?

Four sentences, each delivering distinct value: core function, resolution method, missing-data interpretation, and data-age/future behavior. No filler, well-organized, front-loaded with the primary purpose. Efficient and scannable.

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?

Despite no output schema or annotations, the description covers purpose, resolution, data quirks (missing hours, freshness), and order. For a two-parameter retrieval tool, it is nearly complete. The only minor gap is not explicitly stating the returned values (e.g., funding rate) beyond mentioning mark and index, but that is implied and not critical for correct invocation.

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% (both limit and market are described). The description repeats the resolution mechanism already in the schema ('Resolve by symbol (TSLA) or market id') and adds no new parameter-specific insight. Baseline 3 is appropriate as the schema fully documents parameters; description provides no extra semantic value for them.

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 ('funding series'), a specific resource ('one Lighter perp market'), and a clear scope ('hourly', 'newest first', 'mark and index'). It is clearly distinct from sibling tools like perps_markets (which likely lists markets) and other get_* tools, so an agent can identify its purpose without ambiguity.

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 usage for retrieving funding data and explains how to resolve a market (by symbol or id), but it does not explicitly state when to use this tool over alternatives, nor does it mention any exclusions or preferred contexts. No sibling is named as an alternative for this specific need.

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