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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety burden is lifted; the description adds substantive behavior beyond them: the Ed25519 publisher signature, independent recount co-signatures, provider snapshot hashes, settleable status, and the verification endpoint. It does not discuss error cases or missing-signature behavior.

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 leading "Use when..." clause is well front-loaded, but the first sentence is an overstuffed run-on enumerating every return field, which taxes readability. The verification and endpoint URLs earn their place; the field list could be tightened.

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-shape burden and does so thoroughly (ticker, period, scaled-integer value, status enum, rule version/hash, signatures, feed account), plus verification instructions and the REST equivalent. Nothing an agent needs to call or interpret this tool is missing.

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 coverage is 100%, so baseline is 3, but the description adds real meaning: it clarifies that period is optional and that a month is expressed as YYYY-MM-01, which goes beyond the schema's pattern and "newest when left out" note. Ticker semantics are already fully covered by 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 states a specific resource (the signed Tickerz print for an index) and enumerates exactly what that artifact contains (signature, co-signatures, hash, Solana feed account), so the agent knows this is not the plain index lookup. It never names a sibling (e.g., get_index or receipts) to sharpen the boundary, so it stops short of a 5.

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 when a contract, a venue or a person needs the signed Tickerz print" gives concrete selection context, and the follow-up URLs tell the agent how to verify the result. There is no explicit when-not guidance or named alternative tool, which keeps it below 5.

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