Get Unprocessed Message

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

Annotations declare readOnlyHint=true and the description is consistent with a pure read. With no output schema, the description carries the return-value burden and does so concretely, enumerating `err` subfields (message, code, name, stack) and explaining that `messages` is keyed by inPort. It doesn't say what happens if the message no longer exists (already retried or deleted), which keeps it from a 5.

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?

One sentence, front-loaded with the action and then the payoff ('they usually explain why it failed'). No filler and nothing to trim.

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 single-record fetch with no output schema, describing both returned structures is exactly the needed context. The only gap is lifecycle behavior — what an empty or missing message means — which an agent debugging a parked message might reasonably want.

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?

The single message_id parameter has 100% schema description coverage and already points to list_unprocessed_messages as the ID source. The description adds no format, validation, or lookup guidance beyond that, so the schema does all the parameter work.

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 and resource — 'Read one parked message in full' — and even names the payload fields returned. It implicitly distinguishes itself from list_unprocessed_messages by stressing 'one', but never names that sibling explicitly.

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 clause 'together they usually explain why it failed' implies a debugging use case, so when to call it is inferable. However, there is no explicit routing versus siblings like retry_unprocessed_message, delete_unprocessed_message, or list_unprocessed_messages, and no prerequisites stated.

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