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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, but the description adds substantial behavioral context beyond them: the return shape (per-event factor, cumulative factor, ex-dates, reconstruction formula in meta), a critical limitation on unquantified events (rights issues and demergers), and the price-return vs total-return caveat. It also explicitly instructs never to invent a factor for unquantified events.

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?

The description is front-loaded with the purpose, then usage guidance, then critical caveats. Despite its length, every sentence carries decision-relevant information: scope, trigger conditions, return shape, unquantified-event handling, and dividend exclusion.

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?

No output schema exists, so the description must explain return values, and it does: per-event factor and cumulative factor with ex-dates, plus the reconstruction formula in meta. It also covers key caveats (unquantified events, splits/bonuses only, price-return not total-return), making it complete for an agent to call and interpret the tool correctly.

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 symbol and its two aliases (ticker, identifier). The description adds no parameter-level syntax or format details beyond that, which is the baseline 3 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?

The description states a specific verb and resource: 'Get the split/bonus adjustment-factor timeline for a stock', and immediately bounds scope ('factors cover splits and bonuses only'). It distinguishes the tool from raw price retrieval and from real returns, so an agent can tell what it does 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?

It gives explicit triggering conditions: 'USE THIS when a price move looks impossibly large and you need to know whether it was a corporate action rather than a real return, or when the user asks for raw/unadjusted prices, or asks how to adjust for splits and bonuses.' It also supplies an effective when-not/caution path via the CRITICAL note about rights issues and demergers lacking reliable numeric factors.

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