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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds that the measurement is relative to the chain head, which is real context, but says nothing about what 'lag' means operationally (blocks, seconds, boolean) or what a healthy versus unhealthy response looks like.

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?

A single front-loaded sentence with no filler. The only weakness is that 'Proof indexer' is clipped phrasing that costs a moment of parsing.

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 and no parameters, the description carries the burden of explaining what comes back, and it does not — an agent cannot tell whether it will receive a numeric lag, a boolean health flag, or a status string. For a low-complexity diagnostic tool this is acceptable but leaves a real gap.

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 takes zero parameters, so there is no parameter semantics to compensate for; the baseline of 4 applies. The description correctly implies no inputs are needed.

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 names a specific resource (the proof indexer) and a specific measurement (progress and lag versus chain head), which is clearly distinct from every sibling tool (markets, positions, prepare_*). The verb 'Proof' is unusual phrasing, but the intended meaning (check indexer sync state) is recoverable.

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?

Usage is only implied: an agent can infer this is a diagnostic/precondition check used to confirm the indexer is caught up before trusting other data. There are no explicit when/when-not statements and no guidance on how to act on a lag result.

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