Options chain hour by hour: open interest and IV per expiry and strike, the change over 1h and 24h, the ATM IV path

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

Annotations cover the safety profile (readOnlyHint, openWorldHint), and the description adds genuinely non-obvious behavior: anonymous depth returns only the largest strikes while a key with member depth returns every strike, and data capture begins 2026-09-30 so early queries return short history. One tier-limitation and one data-availability caveat is solid added value; it does not cover rate limits or response shaping beyond that.

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?

Front-loaded with the invocation trigger, then the payload, then the two caveats. Dense but every clause carries information; only the 'ByKaranteli's own hourly capture of every listed venue' phrasing is slightly promotional.

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 carries the return-value burden and does so: OI, mark IV per expiry/strike, 1h and 24h deltas, and the ATM IV path. The access-tier and history-window caveats finish the picture for a 4-param optional-all tool; only pagination/volume limits are unaddressed.

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% with per-parameter descriptions and enums, so the baseline is 3. The description restates venue capture and expiry/strike structure but adds no syntax, defaults, or format detail beyond what the schema already documents.

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 — hourly open interest and mark IV per expiry and strike, plus 1h/24h change and the front expiry's ATM IV path. The scope is precise enough to separate it from a static snapshot, but it never names the neighboring options tools (get_options_snapshot, get_iv_surface, get_options_flow), so the distinction 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 an explicit trigger: 'Call this when the user asks how the BTC or ETH option chain moved today or over the last day.' That is a clear usage context, but it offers no when-not or named alternative for the overlapping siblings, which is what a 5 would require.

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