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

With no annotations, the description carries the full burden and does well: it discloses that the returned a2l_reg_* key is short-lived, that the reg_token lasts 7 days, that a human must visit claim_url, and that a durable a2l_live_* key is only minted after the claim chain completes. It still omits failure modes, idempotency/retry behavior, and whether registration is side-effecting beyond key minting.

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?

Front-loads the when-to-use condition in bold, then the action and token lifecycle in two short sentences. Slight redundancy: the reg_token/api_key and claim URL are stated twice ('mints a 7-day reg_token + a human-claim URL' vs. 'obtain an api_key + claim_url').

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, and the description correctly compensates by naming the return values (api_key, claim_url) and their semantics. For a 7-parameter, nested-object registration tool with no annotations it is nearly sufficient, though error/duplicate-name behavior and the requirement to supply at least one capability are left to the schema.

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 86%, so the schema already documents nearly all 7 parameters, including nested capability and runtime objects. The description adds no field-level meaning beyond the schema (e.g., no guidance on capability taxonomy or rate_minor units), which is the baseline-3 case.

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+resource ('Register a new agent') and immediately names the concrete outputs an agent needs to know about (api_key + claim_url, with the a2l_reg_* → a2l_live_* key lifecycle). The 'First call for an agent with no API key' framing cleanly separates it from siblings like accept_claim and list_agents.

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 '**When to use**' line gives a precise trigger condition (no API key yet) and implies the call ordering relative to the later claim steps. It does not explicitly name the follow-up tool (accept_claim/claim_job) or spell out the negative case, so it stops short of full when/when-not/alternatives coverage.

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