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

Annotations already cover read-only/safe/idempotency, so the bar is lower, yet the description adds substantial context: result ordering, currency unit, and the currently-disabled server state with the exact not_available response and the clarification that it is not about the ticker. That failure-mode disclosure is exactly the kind of trait annotations cannot express.

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 short sentences, each earning its place: purpose first, then parameter behavior, then the critical availability caveat. Front-loaded and free of 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, return values need no explanation, and the description covers what it returns, ordering, units, parameter behavior and the current disabled state. Nothing an agent needs to call it correctly is missing.

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 description coverage is 100%, so the schema already documents limit, since, until, source and ticker. The description mostly restates these (default 20, max 50, source values), adding only the mild framing that since/until 'bound the window'. Baseline 3 is appropriate when the schema does the heavy lifting.

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 ('Recent stored snapshots for one Kalshi perpetual') plus scope, ordering ('newest first') and unit ('in dollars'). The perp-specific framing implicitly distinguishes it from get_history and get_price_history, but it never names those siblings, so differentiation is left to inference.

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?

Gives concrete operating guidance: limit default/max, that since/until bound the window, and the source options. Crucially it warns that the tool is currently switched off and will answer not_available, telling the agent what to expect before calling. It stops short of saying when to prefer this over get_history or get_price_history.

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