Forward a message

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

Adds substantial context beyond the annotations: no file re-upload, recipients see it as forwarded, not_forwardable responses for polls/events/reactions/view-once/deleted and contact stories, and a returned list of queued messages to verify with get_message. Annotations cover mutation/open-world, so the bar is lower, but the failure-mode disclosure is genuinely valuable. Slightly short of 5 only because error/permission context outside the not_forwardable cases is not addressed.

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 core action and scope, then tapers into edge cases; every sentence carries a distinct constraint. It is dense and long, but nothing is redundant enough to cut meaningfully.

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?

Despite no output schema, the description explains the return shape (one queued message per chat in the order of `to`) and how to verify it. Content-type boundaries, dedup behavior, and the sibling alternative are all covered, leaving no gap an agent needs before calling.

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 100%, so the schema already documents messageId, to, and idempotencyKey including formats and the 5-item/forwardedManyTimes limits. The description reinforces the 'up to 5 chats' and forwardedManyTimes constraints but adds no syntax or meaning beyond the schema, so the baseline 3 is correct.

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 (Forward) and resource (a stored message, received or sent) with scope ('to up to 5 chats of the same account'). It explicitly distinguishes itself from the send tools, so an agent can route between forwarding existing content and sending new content without inspecting siblings.

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?

Names the alternative explicitly ('To label new content as forwarded, use a send tool with `forwarded: true` instead') and enumerates which content types are non-forwardable, giving the agent clear when/when-not boundaries. The forwardedManyTimes one-chat-per-call constraint further clarifies selection.

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