copyMessage

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

With no annotations provided, the description carries full responsibility for behavioral disclosure. It explains the lack of a link to the original, the limits on service/paid/giveaway/invoice messages, the quiz poll condition, and the return value. This is a strong disclosure of core behavior, though it does not discuss edge cases like media group behavior or rate limits.

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?

Three sentences, all informative and front-loaded with the core purpose. Every sentence earns its place: the action, the exceptions, the comparison to forwardMessage, and the return type. No filler or redundant restatement of the tool name.

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 having 17 parameters and no output schema, the description covers the crucial invocation context: what can be copied, what cannot, and what is returned. The schema handles the remaining parameter details, so nothing critical is missing for an agent to correctly select and invoke the tool. It could add examples or integration notes, but none are essential.

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 100%, so the schema already documents all 17 parameters in detail. The description adds little parameter-specific meaning beyond what the schema provides; it does not reiterate or enrich parameter semantics. Baseline 3 is appropriate because the schema does the heavy lifting.

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 states a specific verb and resource: 'Copy messages of any kind', then precisely scopes exceptions and an analogy to forwardMessage. It clearly distinguishes itself from forwardMessage by noting the copied message doesn't have a link to the original, so an agent can tell them apart 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?

The description gives explicit context for when to use copyMessage versus forwardMessage: it is analogous but removes the original-message link, which is a clear decision criterion. It lists unsupported message types and the quiz poll condition, providing important constraints. It does not explicitly mention the sibling copyMessages tool or advise when bulk copying is preferred, so some usage guidance is left implicit.

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