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

Annotations already declare read-only, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds that the call is scoped to exactly one context, which is modest value, but leaves unclear whether returned destinations are existing configuration or the set of assignable targets.

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?

A single front-loaded sentence with no boilerplate. It is efficient, though the terse glossing of contexts creates minor ambiguity rather than saving space.

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 one-parameter read tool with a fully described enum, this is close to adequate. Without an output schema, however, the description should explain the shape/nature of what comes back, and it does not.

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% and the enum is fully documented, so baseline is 3. The description glosses seven of the ten contexts ('a number', 'closed hours', 'an unanswered seat'), which adds a little interpretive value but silently omits person_busy, person_decline, and incoming_rule.

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 verb (returns) and a resource (destinations for a routing context), but 'destinations' is ambiguous — configured targets vs. valid choices — and it never says what it is distinct from siblings like get_forwarding or set_number_routing.

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?

No when-to-use guidance, no prerequisites, and no mention of alternatives. Nothing tells an agent whether this should be called before set_number_routing/set_callback_routing or instead of get_forwarding.

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