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

With no annotations, the description carries the full behavioral burden and does substantial work: rate limit (3 keys per IP per 30 days), an edge-case guarantee that past the limit a key is still created at $0 and 'never a silent zero,' no card required, ~5s latency, and nothing to cancel. It does not address idempotency (re-registering the same agent_name) or whether the key is returned only once, which keeps it from a 5.

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 key fact (instant API key + $5 credits) is front-loaded, which is good, but the body is promotional and repetitive — 'no card' appears twice, and phrases like 'no human, no Stripe' and 'credits just sit there' add length without actionable content.

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 2-param registration tool with no annotations and no output schema, the description covers the essentials an agent needs: cost, rate limits, edge-case behavior, immediate usability of the key, and the natural next step (list_products). Remaining gaps (idempotency, exact response shape) are minor given no output schema exists.

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% (both agent_name and email are documented, including that email can be omitted for anonymous registration), so the schema already does the heavy lifting. The description adds no parameter-level detail beyond what the schema provides, making the baseline 3 appropriate.

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 states a specific verb+resource: one call that registers an agent and returns an API key plus $5 credits. 'START HERE' and the mention of querying telemetry/inference make its role as the onboarding entry point distinguishable from siblings like check_balance and list_products. It is clear, though the core action is wrapped in promotional framing.

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?

It gives explicit sequencing ('START HERE', then list_products) and names alternatives: 'Try get_data_dictionary first if you want the coverage spec, or GET https://kairossignal.com/try with zero setup.' Conditions for using it are clear; what's missing is any explicit statement of when NOT to register (e.g., already have a key).

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