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

Annotations already establish read-only, idempotent, non-destructive behavior, so the bar is lower. The description adds real context on top: the auth requirement (api_key from register_agent) and the polling cadence, which is behavioral guidance annotations cannot express.

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?

Three short sentences with no filler, and the dependency on ask_nexus_deep is front-loaded. The parenthetical '(register_agent, no key needed)' is slightly compressed and reads awkwardly, but nothing is wasted.

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?

There is no output schema, so the description must cover return values, and it does: status running|done|failed plus the verified answer when done. Combined with the auth prerequisite and polling cadence, an agent has everything needed to call and interpret this 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% with both parameters documented, so the schema carries the semantics. The description restates where api_key and job_id originate but adds no format, length, or validity detail beyond the schema, 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 ('Poll a deep investigation started with ask_nexus_deep') and explicitly names the sibling that creates the job. An agent can distinguish it from ask_nexus and ask_nexus_deep without opening any 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?

Gives the precondition (job must come from ask_nexus_deep) and an explicit polling cadence of every 20-30 seconds, which is genuinely actionable. It does not name a when-not case or an alternative retrieval path, so it stops short of a 5.

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