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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds genuinely new behavioral context: result ordering (newest first), page size (50 per page), and the default all-platforms merge scope.

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, zero filler, with the resource, ordering, and pagination constraint front-loaded before the platform-narrowing caveat. Every clause 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 low-complexity, zero-required-parameter list tool with annotations already carrying the safety profile, the description covers scope, ordering, and pagination adequately. It does not mention total counts or the shape of returned account records, but that gap is minor and no output schema exists to fall back on.

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 description coverage is 100% and both parameters are fully documented there, including the enum values and the 'omit for every platform, merged newest-first' note. The description mostly restates page size and platform narrowing, adding little beyond the schema, so the baseline 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?

States a specific verb and resource ('List the authenticated user's posting accounts'), scoped to three named platforms, which cleanly separates it from get-account-tool, create-account-tool, and the submission/phone listing tools. The 'authenticated user's' qualifier pins down whose accounts are returned.

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 sentence 'Every platform is included unless `platform` narrows it to one' describes scope behavior, implying the tool is for enumerating accounts across or within a platform. However, there is no explicit when-to-use guidance versus siblings such as get-account-tool for a single account, nor any stated prerequisites.

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