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

With no annotations, the description carries the full burden and does well on several axes: it discloses field filtering ('keeps the fields you include'), a non-charging failure mode for missing required fields, encryption at rest, and the return payload (locker id + key + manifest). It omits auth/permission requirements, what ttl_days does to packet lifetime, whether packets are immutable or overwritable, and rate/cost behavior beyond the production price note.

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?

Core behavior is front-loaded in the first two sentences with no filler, and each clause adds information (filtering, refusal, storage, return values). The trailing parenthetical about AYNE playzone, production endpoint, and $0.002 pricing is operational detail that slightly dilutes focus but is short and arguably useful for callers.

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 6-parameter tool with a nested object, no annotations, no parameter descriptions, and no output schema, the description covers purpose, failure semantics, and the return shape reasonably well. Gaps remain around ttl_days semantics, the 'to'/'from' roles, and the packet object's expected contents, which an agent would have to guess.

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 0% across 6 parameters including a nested 'packet' object, so the description must compensate. It does explain 'include' (kept fields) and 'required' (refusal trigger) and implies 'to'/'from' via the handoff framing, but 'ttl_days' is never mentioned and the structure of the 'packet' object is left entirely to the schema.

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 opens with a concrete verb+resource ('Handoff Packager: hand a job to another agent') and states the outcome (encrypted packet in an Agent Locker returning id, key, manifest), which separates it from retrieval siblings like locker_get/locker_put without naming them. It is specific about what is produced, though it never explicitly contrasts with those sibling tools.

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 phrase 'hand a job to another agent with only what it needs' implies the use case (minimal-context transfer between agents), and 'refuses (no charge) if required fields are missing' signals a precondition. There is no explicit when-not guidance and no named alternative for cases like simply storing or fetching a locker entry.

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