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

The description adds significant behavioral detail beyond the readOnlyHint/idempotentHint annotations: synced is based on a 0.9999 verification threshold rather than a simple height comparison, and while it is false, reads may be stale but writes still work. This is exactly the kind of non-obvious runtime behavior an agent needs to interpret results correctly.

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 first two sentences are tight and front-loaded with the tool's purpose and access requirements. The later paragraphs are longer, especially the expiry/block-rate explanation, but they provide genuinely useful operational context rather than filler, so the description remains earned even if slightly dense.

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?

For a parameterless, read-only status tool with an output schema and readOnlyHint/openWorldHint/idempotentHint annotations, the description covers everything needed: what the tool checks, what the synced field really means, how it relates to read_record, and authentication expectations. There are no missing gaps that would prevent correct invocation or interpretation.

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?

There are zero parameters, so the schema leaves nothing to explain; the description explicitly confirms 'no parameters' and 'no sign-in required'. This matches the baseline for a parameterless tool and adds no unnecessary param detail.

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 clearly states a specific action ('Check that the chain node behind this service is healthy and fully synced') and lists the exact fields reported: version, block height, header height, peer connections, and sync state. It does not explicitly name a sibling tool for differentiation, but the domain and scope are unambiguous enough that an agent can distinguish it from read_record, register_identity, and the others.

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 gives clear context for when to use this tool: when you need to verify node health and sync status, and it explains the implication that a false synced flag may mean read_record reflects an older chain state. It does not explicitly say 'use this instead of X', but it provides enough operational guidance for correct use.

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