list_pending_actions

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

Annotations already declare readOnly/openWorld/idempotent/non-destructive, so the safety profile is covered. The description adds genuinely non-obvious behavior beyond that: a live upstream OpusDNS read for routed customers and an empty payload with no upstream call for everyone else, which explains why an apparently empty result may be normal.

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 compact sentences, with the resource scope front-loaded and the behavioral caveat second. The bracketed '[GET /v1/domains/pending-actions]' is minor implementation detail but does not pad meaningfully.

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 read-only list tool with full annotation coverage and no output schema, the description covers purpose, scope, and the empty-result behavior. Only the return shape is unaddressed, which is a mild gap in the absence of an output 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?

There is a single optional parameter (x-trace-id) with 100% schema description coverage, so the schema carries its meaning entirely. The description adds nothing about the parameter, making the documented baseline of 3 the correct score.

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 gives a specific verb and resource ('List pending domain actions') and then defines the resource precisely: domains with an unacknowledged outbound transfer (ACK/NACK) pending. That scoping lets an agent distinguish it from the sibling list_domains without inspecting either schema.

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 condition that selects this tool is stated explicitly — you want domains awaiting ACK/NACK — which implicitly routes the agent away from plain list_domains. It does not name the alternative or state when not to use it, so it falls short of a full 5.

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