postbag_bags

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds real value on top: what is excluded (letter bodies, credentials, custom ledger paths), that errors still return readable rows, and that pagination can shift under concurrent bag changes. It does not contradict the annotations.

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?

Front-loaded with the purpose, then compact sentences for exclusions, error behavior and pagination. The trailing 'version reports...' sentence is orphaned (no version parameter or return field defined here) and reads as noise in an otherwise tight description.

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 an output schema present and annotations covering safety, the description only needs to add exclusions, failure behavior and pagination caveats, all of which it does. The unexplained 'version' note and thin limit/offset semantics keep it from being fully complete.

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?

Two parameters (limit/offset) with 0% schema description coverage, so the schema only supplies types, defaults and bounds. The description's pagination-instability note is relevant to offset semantics, but it gives no guidance on the limit/offset relationship or max-window behavior, so compensation is partial.

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 (Inventory) and the exact resources enumerated: default/named bags, letter counts, and peers, plus the negative scope 'without probing sessions'. That is enough to separate it from postbag_read/send, though no sibling is named explicitly, so it stops short of the top band.

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 only implied: it is the listing/inventory counterpart to postbag_read, and 'without probing sessions' hints it is the cheap option. There is no explicit when-to-use, when-not, or named alternative (e.g. join/leave/read), leaving the agent to infer routing.

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