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

With readOnlyHint=false and destructiveHint=false already structured, the description adds real value: atomic registration+first receipt, owner key shown once and needing secure storage, default private with explicit public sharing, and a warning not to fabricate monitoring activity. It doesn't describe rate limits or what happens on duplicate registration, but the mutation/auth-sensitive traits are surfaced.

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-loaded with the core action, then packages mode behavior, the one-time owner key, and privacy defaults into a few tight sentences. A stray line break splits a sentence but the content is dense with little waste.

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?

The description is adequate for a 12-param registration tool with annotations and an output schema: it covers safety, the one-time secret, and mode toggles. But with 0% schema coverage it leaves nine parameters unexplained and doesn't say what to do with the returned owner key beyond 'store securely,' which an agent needs in order to configure follow-up heartbeat calls.

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 0%, so the description carries the param burden but only explains three of twelve parameters (mode, start_heartbeat, visibility, plus endpoint_url implicitly for probe mode). It says nothing about contact, agent_type, webhook_url, checks_config, heartbeat_enabled, check_interval_sec, or heartbeat_interval_sec, which is a significant gap at 12 params.

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?

Description opens with a clear verb+resource: "Register a real worker once," and distinguishes two operating modes (heartbeat vs. probe) that no sibling name conveys. It's specific about the resource being a monitoring registration, though the existence of sibling tools like update_agent_health and agent_health_heartbeat means an agent must infer 'register' means the initial creation step rather than an update.

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 a conditional for start_heartbeat=true and says probe mode requires a deployed readiness URL, plus a visibility default. But it never states when to choose this tool over siblings like update_agent_health, attach_agent_endpoint, or subscribe_liveness, so the agent gets mode guidance without routing guidance.

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