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

No annotations are provided, so the description carries the full behavioral burden, and it discloses nothing beyond the mutation implied by 'Mark'. There is no statement about idempotency (what happens if already marked going), auth requirements, or whether the state change is reversible. 'Requires listing_id' is parameter information, not behavior.

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 very short sentences, front-loaded with the action and target state. The second sentence is mildly redundant given the schema already flags listing_id as required, but it is not wasteful enough to penalize heavily.

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 a simple one-parameter mutation with no output schema, the mechanics are nearly covered, but with no annotations and ambiguous 'going' semantics (RSVP? bookmark?), the definition leaves the agent guessing about consequences and confirmation of success.

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% for the single parameter, and the schema already documents listing_id as the dayplay listing id and marks it required. The description only restates that it is required, adding no format, source, or lookup guidance 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?

States a specific verb (Mark) and resource (a listing) with the target state (as going), so an agent can see it is the inverse of unmark_going. However, 'going' is domain jargon and the description never differentiates this from siblings like save_listing or list_going, so the differentiation is only implied by the name.

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, no mention of the obvious alternative unmark_going or list_going, and no stated preconditions (e.g. must the listing exist, must the user be authenticated). The agent must infer usage entirely from the name.

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