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

With readOnlyHint=true, the safety profile is covered by annotations. The description adds useful context about data availability (since April 2018, any minute) and the included fields (BSM greeks, IV, OI), but it does not disclose return format, pagination, rate limits, or access restrictions beyond the 'Alpha tier' mention. This is comparable to mid-tier transparency with annotations.

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, front-loaded with the core purpose and followed by filter capabilities. No fluff or repetition of schema details; 'Alpha tier' is a concise optional note. Every sentence earns its place.

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?

Although there is no output schema, the description indicates what is returned (option chain with BSM greeks, IV, OI) and the temporal scope. It covers key aspects of a historically-focused read tool. It does not detail pagination or output structure, but the description is reasonably complete given the rich schema and simple read-only nature.

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 baseline is 3. The description repeats that filtering is possible by expiry, strike, and type, but adds no new meaning beyond the schema. It does not mention maxSpreadAbs/maxSpreadPct filters, but those are already documented in the schema.

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 uses the specific verb 'Replay' and clearly identifies the resource: the full option chain with BSM greeks, IV, and OI. It distinguishes from siblings by specifying historical granularity ('at any minute since April 2018') and by mentioning the option chain, separating it from current quote tools like get_option_quote and get_option_chain.

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 the use case (historical replay) but does not explicitly state when to use this tool vs alternatives or provide exclusions. It mentions filtering by expiry, strike, and type, giving some context, but lacks guidance on when not to use it or which sibling tools are more appropriate for current quotes.

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