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

Annotations declare readOnlyHint=false, idempotentHint=false and openWorldHint=true, and the description adds real context beyond that: this is a blocking long-poll with a default wait, a ~30-second line-hold window after failure, and re-invocation as the correct recovery. The one meaningful gap is whether a returned call is consumed/removed from the queue, which matters given the non-idempotent hint.

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 operating instruction is front-loaded and every sentence carries information — default duration, unattended mode, error recovery. It is dense with nested parentheticals and long clauses, which slows scanning but does not add filler.

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?

With no output schema, the description does describe the three outcome categories an agent must handle and what to do after each, plus the timeout range. It stops short of describing the shape of the returned call object, but the outcome-level description is enough to branch correctly.

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 decision-relevant meaning: seconds should sit just under your own tool-call timeout, and longer waits save turns for always-on agents. The secret guidance (omit it when the connector already carries it, never echo it) also adds a safety rule beyond the schema text.

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 (wait) and resource (calls on your line) and defines the return condition: a ringing call, a screened stranger, or nothing. It also names the follow-up siblings (answer_call, let_in) that handle each returned outcome, letting an agent distinguish this long-poll tool from the action tools without opening schemas.

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 explicit operating modes: default ~25s wait between steps while working, versus sitting on the line with seconds near your tool-call limit when running unattended (always-on agent or routine). It also gives a recovery rule — if a wait errors, call again at once because the line stays held about half a minute.

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