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

Annotations cover the safety profile (idempotent, non-destructive, not read-only), and the description adds genuinely useful behavior: the return value (the checklist as it now stands), the refusal case for a token that acts for no person, and the semantic that 'reached' stays false until SHIP sees the step done.

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?

Dense but front-loaded: the core action and the step/group distinction come first, and side details (return value, refusal) come later. The semicolon-heavy run-on sentences are slightly harder to parse than ideal but every 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?

With no output schema, the description compensates by stating the return value, the refusal condition, and the relationship to setup progress. Nothing critical is missing for an agent to invoke it correctly.

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% and all three parameters are enum-documented, so the schema carries the load. The description clarifies the intent of step vs group (one milestone vs every open step of a group), which adds modest value beyond the schema but no new format or constraint detail.

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 step of the setup checklist) with the exact state transitions available (completed/skipped/open). It is clearly distinguishable from the sibling get_setup_progress, which is pointed to as the source of step ids.

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?

Explains the two modes clearly: give 'step' for one milestone, or 'group' to mark every open step of a group (the console's Skip all). It also notes open removes the mark. It stops short of explicit when-not-to-use guidance, but the routing between step and group is well covered.

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