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

Goes well beyond readOnlyHint/openWorldHint by disclosing the auth prerequisite (CommuteScout API key), the degraded state (connected=false with a message explaining how to connect), and a privacy constraint about not repeating the data to others. These are operationally critical traits an agent could not infer from annotations.

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?

Three short paragraphs, each front-loaded with a distinct concern: what the data is, when to call it, and how to handle it safely. No filler or repetition.

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 zero-param read tool with no output schema, the description covers the resource, the auth-dependent failure mode, the return signal, and the privacy handling — everything an agent needs to call it and interpret the result responsibly.

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?

Zero parameters, so baseline is 4. The description adds value by naming two response fields (connected, message) that govern whether the call succeeded, compensating for the absence of an output 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 resource (the user's saved places: Home, Work, favorites, recent destinations) and its origin (synced from CommuteScout site and apps). This is clearly distinguishable from siblings like find_place or check_route, which deal with arbitrary locations rather than the user's personal saved set.

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?

Explicitly scopes usage: 'the trip tools already accept "home", "work" or a place's name directly, so call this only to show or choose among them.' It names the alternatives and the precise condition (display/selection) under which this tool is the right call.

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