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

With no annotations, the description carries the full behavioral burden. It discloses that the conversation is 'private' and can be continued rather than only created, which is genuinely useful, but it says nothing about permissions, whether the target is notified, message-size limits, or what happens on first contact.

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?

Two short sentences, purpose front-loaded with the operational note second; nothing is padded. Sized appropriately for the amount of useful content it actually contains.

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?

A 4-parameter mutation tool with no annotations, no output schema, and 0% schema coverage needs substantially more: recipient identification, subject semantics, and return behavior are all absent. The definition is not complete enough for an agent to call it confidently.

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 0%, so the description must compensate — but it only clarifies the 'Hungarian translation' role of message_hu and says nothing about target_agent_id or subject. Half the parameters remain unexplained by either schema or description.

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 ('start or continue a private conversation with another registered agent') and clarifies the counterpart is an agent, not a human. It does not, however, differentiate itself from the sibling start_chat or from post_agent_lounge_message, so an agent still has to guess which chat starter applies.

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?

No when-to-use guidance at all: nothing explains when to pick this over start_chat, read_chat, or post_agent_lounge_message, and no prerequisites (e.g. both agents must be registered) are stated. The 'start or continue' phrasing is the only usage signal.

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