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

Annotations only declare readOnlyHint=false, openWorldHint=true and destructiveHint=false, so the description carries real weight and does: it discloses that publishing is external/irreversible-feeling, that media is REQUIRED for Instagram/TikTok/YouTube/Pinterest except drafts, and enumerates per-platform transformation rules (carousel cropping, LinkedIn PDF conversion, YouTube thumbnail verification limits). It does not state what identifiers are returned or failure/partial-success behavior across multiple accountIds, which is the notable remaining gap.

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-loaded with the action and the three modes, and nearly every clause carries a platform-specific constraint that an agent genuinely needs. It is dense to the point of being a wall of text, however — the platform rules would scan far better as a list, and some detail (thumbnail resolution, character limits) borders on optional.

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 an 18-parameter tool with nested settings objects and no output schema, the description does the heavy lifting on platform-dependent requirements and conditional validity, which is where mistakes would happen. Drop-offs are the lack of any statement about the response shape or what happens when one of several accountIds fails.

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%, so the baseline is 3, but the description adds cross-parameter semantics the schema cannot express: scheduledAt is in workspace timezone, pinterestBoardId is required when targeting Pinterest, and it explains how content/media are reinterpreted per network (first line = title, first photo = cover). It stops short of explaining idempotencyKey, which the schema handles well on its own.

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 first sentence gives a specific verb and resource plus the three operating modes (schedule, publish now, draft), which immediately distinguishes it from siblings like update_post or upload_media. An agent can tell what this tool does without opening 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?

Explicitly routes the agent to siblings: 'use upload_media first for reliable hosting' and 'use list_pinterest_boards' for board ids. It also states the conditions that select each mode (explicit time, next free slot, publishNow, draft), so the branching is unambiguous.

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