get_today_time_blocks

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

Beyond the readOnlyHint annotation, the description discloses a real limitation (MarvinAPI issue #65) and explains the workaround: the mapping is fetched separately from plannerSmartLists using a normalized block title. This is exactly the non-obvious behavior an agent needs to interpret the response and the extra API call.

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, front-loaded with the core purpose and followed by a focused limitation note. Every clause contributes either a use case or behavioral context; there is no redundant filler.

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?

Given the readOnly annotation, an existing output schema, and full parameter coverage in the schema, the description covers the tool's main behavioral quirk and mapping semantics. It does not explicitly position the tool against similar siblings such as get_time_tracks, leaving a minor selection gap.

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?

The schema already documents both parameters at 100% coverage, so the baseline is 3. The description adds meaning by explaining why include_category_mapping exists and how the mapping key works (normalized block title), which goes beyond the schema's terse '1 extra API call' note.

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 and resource: "Get today's time blocks with their category or smart-list mapping." This clearly states what is returned and differentiates the tool from siblings like get_time_tracks by emphasizing the category/smart-list enrichment.

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 described use case is clear: call this when you need time blocks and their category/smart-list mapping for today (or any date via the date parameter). It does not name alternative tools or state explicit when-not-to-use conditions, so it stops one step short of the top score.

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