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

No annotations are supplied, so the description carries the full disclosure burden. It signals an on-chain read but says nothing about the returned value (boolean? record?), latency/RPC dependency, or behavior for unknown chains — all of which an agent needs for a tool with zero structured behavioral hints.

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?

One short, front-loaded sentence with no filler, appropriate for a simple predicate tool. It is efficient but borders on under-specified rather than optimally sized.

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 annotations, the description should at minimum state what the check returns and how failures/unsupported chains are surfaced. Neither is covered, leaving a real gap for an agent that must interpret the result.

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% and the chain parameter already documents its enum, default, and the Sepolia exclusion. The description adds nothing beyond the schema for either agentId or chain, so the baseline of 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?

"Check whether an agent ID exists on-chain" gives a specific predicate and resource, which is clearly distinct from siblings like actora_identity_get (fetch details) or actora_identity_list (enumerate). It stops short of naming those siblings explicitly, so it is clear but not fully differentiated.

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?

There is no guidance on when to use this versus actora_identity_get or actora_identity_list, and no stated prerequisite (e.g. use before register, or that a false result means the ID is unclaimed). The existence-check use case is only implied by the verb.

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