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

The description adds real behavior beyond the annotations: a 30-minute expiry window, a hard cap of 3 holds per workspace, and idempotent repeat behavior that returns the existing hold instead of creating a second one. Annotations only supply title/openWorldHint/destructiveHint, so these constraints are genuinely additive. It stops short of saying what happens to the number at expiry or whether holds carry any billing implication.

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?

Three tight sentences: purpose and expiry first, then the quota limit, then idempotency. Zero filler and nothing important is buried.

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 two-parameter, non-destructive tool with no output schema, the description covers timing, limits, and repeat semantics well. The one gap is the return shape — it says a repeat 'returns the existing hold' but never says a hold identifier comes back, which an agent would need to release or convert the hold.

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 both parameters — inventory_id and the standard 'purpose' field — are documented in the schema itself, including the pointer back to desk_search_numbers. The description adds no parameter-level detail, so the baseline of 3 applies.

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 names a specific verb and resource — holding an available number — and adds the concrete scope of 30 minutes plus the rationale (prevents others, including free trials, from taking it). It is clearly distinguishable from desk_claim_number and desk_release_number_hold in spirit, but it never names those siblings, so an agent must infer the boundary itself.

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 implied rather than stated: the hold exists 'while the buyer decides,' which suggests a pre-purchase state. There is no explicit when-not guidance (e.g. use claim_number to actually acquire, release_number_hold to give it up early), and the quota note reads as a constraint rather than routing advice.

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