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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuine value beyond that by enumerating the returned payload (current stop, visited/remaining stops, percent done, practice stats, limits, resume line), which matters because there is no output schema.

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 sentences, zero waste, with the trigger condition front-loaded and the return contents following. 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 one parameter, no output schema and full annotation coverage, the description is nearly complete for a safe read tool, and it compensates for the missing output schema by listing return fields. It omits edge-case behavior, such as what happens with an expired or invalid session handle.

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 the single parameter is fully documented, including provenance ('from open_journey') and the cxs_ prefix. The description adds no parameter guidance at all, so the baseline 3 applies.

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 ('get journey progress') and adds a user-intent framing ('where they are in a journey, how far they have come or how much is left') plus an enumeration of returned data. It does not explicitly distinguish itself from get_resume_link or open_journey, though the 'resume line' mention hints at overlap.

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?

Gives clear trigger conditions tied to user phrasing ('Use when the user asks where they are...'), which is directly actionable. It stops short of naming exclusions or pointing to alternatives such as get_resume_link for a shareable link.

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