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

Annotations only declare the safety profile (readOnly=false, destructive=false, idempotent=false, openWorld=true); the description adds substantial independent behavior — draft-by-default vs deferred publication for scheduled posts, network-dependent treatment of extra content blocks, silent IGNORING on some networks, and the presence of a `warnings` field in the response. This is context the agent cannot derive from 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?

The content is dense and well front-loaded (purpose, then content semantics, then scheduling, then media/options, then exclusions), with no filler sentences. It is long for a tool description and the trailing French restatement duplicates information already given in English, which costs a point on tightness.

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 mutating, nested-object tool with no output schema, the description covers creation mode, scheduling semantics, per-network side effects, media binding, option validation, and even flags the `warnings` response field. Nothing an agent needs to call it correctly 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 83%, yet the description still adds real semantics: the string-vs-array duality of `content` and what the second element becomes per network, that media land on the first block, that `options` is keyed by provider name from list_accounts, and that unknown keys or un-targeted providers are rejected. This goes beyond restating schema text.

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?

Opens with a specific verb+resource ('Create a post in PurrPlan') and immediately scopes it to connected social accounts, then explicitly rules out stories and names create_stories as the sibling for that case. An agent can distinguish it from create_stories without reading 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?

Explicitly states the default behavior (creates a draft), the alternative path (pass scheduled_at to schedule), the explicit exclusion (not for stories; use create_stories or the type:story option), and the media prerequisite via upload_media_from_url. When-to-use, when-not-to-use, and alternatives are all present.

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