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

Annotations already cover safety/idempotency (readOnlyHint=false, idempotentHint=true, destructiveHint=false, openWorldHint=true), but the description adds non-obvious operational constraints: the download URL must be host-provided, must never be synthesized from generated-image identifiers or sandbox paths, and arbitrary websites must not be fetched. This is real added context about input provenance rather than a restatement of 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-loads purpose, then alternative, then constraints — a sensible order. Four sentences are dense and mostly earn their place, though the Publinio sentence is client-specific context that a third-party agent could skim past.

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?

An output schema exists, so return values need not be explained, and annotations cover idempotency and safety. The description covers sibling routing and URL provenance, but says nothing about permission requirements, failure on duplicate imports, or accepted mime types — minor gaps for a 3-param mutation tool.

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 0%, so the description must carry semantics; it does explain the critical constraint on file.download_url (must be a genuine host-provided URL). However, brandId, file_id, file_name, mime_type, and idempotencyKey receive no explanation, leaving half the nested object's fields undocumented.

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+resource ('Import one file ... into the selected brand library') with the source channel named (supported ChatGPT file handoff). It explicitly distinguishes itself from import_media_batch, so an agent can route single-file vs batch imports without opening either 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?

Gives explicit routing: use import_media_batch for multiple images or carousel slides; other clients should use existing brand media or upload in Publinio. It also states an exclusion — 'Do not fetch arbitrary websites' — covering both when-to-use and when-not-to-use.

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