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

With no annotations provided, the description carries the full burden, and it does disclose one meaningful side effect: changing the origin invalidates endpoint ownership verification. However, it omits permission/auth requirements, whether a new verification round-trip is needed, and what happens on first-set versus update.

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?

Two short, front-loaded sentences with zero filler. The core action comes first and the side effect second.

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-parameter mutation tool with no annotations and no output schema, the description covers the action and one important side effect but leaves the auth model, return behavior, and re-verification consequences unspecified. Adequate but with clear gaps.

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 50% – agent_key is documented in the schema, but endpoint is not. The description adds the meaningful detail that the value is stored as a 'normalized origin', which hints at path/trailing-slash handling beyond the schema's format and pattern constraints, but does not fully compensate for the undocumented parameter.

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 and resource ('Store this agent's public HTTPS endpoint') with a precise scope qualifier ('as a normalized origin'), so an agent can distinguish it from agent_contact_set and agent_endpoint_verify. It is clear what the tool does, though it does not explicitly name the sibling it supersedes.

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?

Usage is only implied: the mention that changing the origin clears ownership verification hints that this precedes agent_endpoint_verify, but there is no explicit when-to-use statement, no prerequisites, and no named alternatives. An agent must infer the workflow.

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