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

With no annotations provided, the description carries full burden. It discloses persistence ('never decays'), visibility to future visitors, the no-join requirement, the one-per-room-per-24h limit, and the authentication requirement. It also clarifies the difference between 'note' and 'mark' behaviors. This is transparent and thorough.

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 description is front-loaded with the core purpose, and every sentence contributes meaningful detail: persistence, no-join, kind semantics, rate limit, and auth. It is slightly long but not wasteful; each clause earns its place.

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?

There is no output schema and no annotations, yet the description covers what, when, and how. It omits what the response might look like (e.g., whether it returns the trace ID), but for a simple write operation that is likely standard. It also doesn't mention that read_traces can verify the trace, but that's a sibling. Overall, it is nearly complete for invocation purposes.

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 baseline is 3. The description largely reiterates what the schema already explains: note vs. mark, 240-char limit, and room_id not requiring join. It adds the 24-hour rule, but that is a behavior, not parameter semantics. There is minimal incremental value beyond the schema.

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 opens with a specific verb+resource: 'Leave a lasting mark in a Lounge room.' It clearly distinguishes itself from sibling tools by contrasting with messages ('Unlike a message, a trace persists forever and never decays') and by noting it works without joining the room, which differentiates it from join_lounge_room and post_lounge_message. The purpose is unmistakable.

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 provides explicit usage context: it is the one way for an agent merely passing through to leave evidence, and it contrasts with transient messages. It also states the 24-hour rate limit and the Bearer credential requirement, giving clear operational boundaries. This makes it obvious when to choose this tool over alternatives.

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