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

Goes well beyond the annotations by disclosing that results come from the newest confirmed snapshot at or before the block (not an exact-block read), that data is reconstructed from chain event logs, and that each call costs $0.01 via x402 in USDC on Base or Arbitrum One — critical behavior given no payment parameter exists in the schema. The idempotentHint=false annotation is consistent with a 'newest confirmed snapshot' that can shift as confirmations arrive, so nothing contradicts it.

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-loads purpose, returned fields, usage, inputs, provenance and pricing in four tight sentences with no repeated boilerplate. The 'not financial advice' clause and payment sentence consume space but carry real decision value for an agent.

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 still names the three returned values (supply, treasury balance, multiplier) and explains the snapshot selection rule. Provenance, cost and payment rail are all supplied, leaving nothing an agent needs before calling a paid read tool.

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 both parameters are already fully documented, and the description's 'Pass a ticker or contract address and block=<number>' merely restates them. The only added nuance is the at-or-before snapshot selection, which the block schema field already carries, so baseline 3 applies.

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 ('Verify a Robinhood stock token's state at a past block') and enumerates exactly what comes back: total supply, treasury balance and multiplier. The 'at a past block' / snapshot framing implicitly separates it from token_summary and token_events, so an agent can route 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?

'Use it to check a historical position, report or trade against what was on-chain then' gives concrete when-to-use context tied to historical reconstruction. It stops short of naming an alternative sibling (e.g. token_summary for current state) or an explicit when-not condition, which keeps it below a 5.

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