Register agent

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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent, closed-world write; the description goes well beyond them with the auth scope requirement, the idempotency-adjacent uniqueness rule (same derived slug → 409), concrete error codes (400 UNKNOWN_AGENT, 409), and the shape of the response (id, slug, wire-up steps) despite there being no output schema.

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?

Four tight sentences with the scope requirement front-loaded, then purpose, then conceptual model and monitor relationship, then uniqueness/error behavior. No sentence is redundant and each adds a fact an agent needs to call this correctly.

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?

Complete for a two-parameter, no-output-schema write tool: auth, return payload, relationship to monitor tools, failure modes, and duplicate-name behavior are all covered, leaving nothing material for the agent to infer.

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%, so the baseline is 3, but the description adds real meaning beyond the schema: it explains the consequence of slug derivation (duplicate names are refused rather than creating a second agent) and how the returned id/slug are consumed downstream by agent_id. It still doesn't elaborate on the optional description field, which the schema already covers.

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 ('Registers an autonomous agent in the project's agent registry') and even names the created artifact and return values (id, slug, wire-up steps). It distinguishes itself from siblings by explaining that this is not an implicit create path (agent_id pointing at a missing agent is a 400, not a create), separating it from create_monitor/update_monitor which only attach monitors to an existing agent.

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 an explicit prerequisite ('Requires the write scope or higher') and clear when-to-use context: call this to create the agent, then use create_monitor/update_monitor to attach monitors via agent_id. It also states when NOT to expect creation (unknown agent_id is never an implicit create) and that re-registering an existing name is refused with 409.

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