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

With no annotations provided, the description carries the full burden of behavioral disclosure, and it excels. It details the 15-minute refresh interval, the fail-closed behavior with calendarStale and dataNote, and explicitly states that no announcement feed is used (everything is read from contracts and the chain). It also mentions observedAt/observedBlock, giving a full picture of data provenance and staleness handling.

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 a single dense paragraph, but it is well-structured: it starts with the core purpose, then explains the two modes, lists relevant fields, and concludes with behavior and failure handling. Each sentence adds unique value, and the information is front-loaded with the main verb and resource. It is not overly verbose given the complexity of the tool.

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?

Since there is no output schema, the description must fully explain what the tool returns, and it does. It lists the data fields (current/pending multiplier, ratio, effectiveAt, secondsUntil, observedAt/observedBlock), explains the two directions, and details the stale behavior. For a tool with no parameters, this is exceptionally complete and leaves no critical ambiguity for an agent deciding to call it.

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?

The tool has zero parameters, so the input schema is empty and schema coverage is trivially 100%. Per the rubric, a baseline of 4 is appropriate. The description does not need to explain parameters, but it adds useful context about the fields returned (newUIMultiplier, effectiveAt, ratio, etc.), which enriches the agent's understanding beyond the bare 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 opens with a specific verb and resource: 'ERC-8056 corporate actions on tokenized stocks, both directions in time.' It clearly names the two modes (pending and log) and explains what each represents, distinguishing the tool from generic stock data tools. It is not a tautology and provides a precise, actionable definition.

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 provides clear context on when to use the pending mode (forward calendar of announced splits/dividends) versus the log mode (past transitions from transfer ratios). It does not explicitly mention alternative sibling tools like get_stock_multipliers, but it gives enough detail for an agent to infer the appropriate use case. No exclusions or when-not-to-use guidance is offered, but the dual-mode explanation is a strong usage guide.

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