account_inventory

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

With no annotations, the description carries the full burden, and it does disclose two useful traits: the exact content returned (mode matrices, last probe, kill-switch) and that no credential values are ever exposed. However, it never states that the operation is read-only/side-effect-free, nor anything about ordering, pagination (none expected with zero params), or authorization requirements.

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?

Two sentences with no filler: the payload is front-loaded, and the security assurance ('No credential values exist in this system') is stated immediately after. Every phrase earns its place.

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 zero-parameter read tool with no output schema and no annotations, the description is nearly sufficient: it enumerates the fields the caller will receive and rules out credential exposure. Minor gaps remain around whether results are ordered/complete and whether the call has any side effects, but not enough to prevent correct invocation.

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 tool takes zero parameters, so there is no parameter semantics to explain; the baseline for a zero-param schema is 4. The schema has an empty properties object and the description correctly implies no inputs are required.

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 resource is named precisely ('All registered accounts') and the payload is enumerated (declared + effective mode matrices, last probe, kill-switch state), which implicitly distinguishes it from the mutating sibling account_set. It stops short of a full verb-first statement like 'List accounts', but an agent can identify what the tool returns without opening anything.

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?

There is no statement of when to use this versus alternatives such as account_set or receipt_list, and no prerequisites, filters, or exclusions are given. The read-only intent is only inferable from the word 'inventory', which is the same gap seen in typical one-line update descriptions.

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