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

Annotations cover the safety profile (read-only, idempotent, non-destructive), and the description adds substantial context beyond them: previews are rasterised approximations with specific simplifications (glass/blur, pan-zoom, exotic gradients), `fidelity.exact=false` signals approximation, preview URLs expire on a 14-day cleanup while `exportUrl` is permanent, and `knownDesignVersion` lets unchanged decks skip re-rendering. This is materially useful behavior an agent would otherwise have to infer.

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?

It is front-loaded with the mode split and the primary capability, then layers caveats in a defensible order. It runs long with heavy bold emphasis and some density around export/preview URL lifetimes, but nearly every sentence carries an operational constraint rather than filler.

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 seven parameters and no output schema, the description carries the burden of describing the response shape — per-slide preview URLs, copy headlines, paid-background flags, and a fidelity report — and it also explains the durability of `exportUrl` versus ephemeral previews. Nothing an agent needs to call this correctly and interpret the result is missing.

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 already 100%, yet the description still adds semantics the schema cannot: `deckId` omitted flips the tool into list mode, `knownDesignVersion` suppresses re-rendering when unchanged, and `slideIds` re-renders only the edited slides for cheap polling. That is interaction-level meaning rather than a restatement of field descriptions.

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 names a specific verb and resource — 'Read one of the user's Instagram carousel decks (or list them all)' — and immediately flags the distinguishing feature: server-rendered slide previews. The dual list/detail mode is stated in the first sentence, so an agent can separate it from siblings like antix_export_deck or antix_get_instagram_audit without inspecting the schema.

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?

It gives explicit routing rules: omit `deckId` to list newest-first, pass `deckId` for the full deck, and use `antix_export_deck` when an actual file is needed for a scheduler, uploader or download. It also gives a hard negative ('do not promise posting to Instagram') and a recovery rule for `previewStatus:"partial"` — call again, don't assume failure.

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