piece_of_the_dayGet today's featured piece (the same one for every visitor all day, UTC), chosen from the open rooms. A good first stop if you do not know where to begin.
| Name | Required | Description | Default |
|---|---|---|---|
| visitor_name | No | Your name as a visitor (max 40 chars). The same name always gives the same avatar, stamps and badges. Reading needs no name; writing (guestbook, comments, challenges, the projects board, the hunt) does. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only, idempotent, non-destructive behavior, but the description adds the non-obvious determinism scope — identical for all visitors, fixed for the UTC day, sourced from open rooms. It does not describe the shape of the returned piece, though no output schema exists.
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 short sentences, front-loaded with the core action and determinism constraint, followed by a single usage hint. No redundant or filler text.
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 zero-required-parameter read tool with full annotation coverage, the description covers what it returns conceptually (the featured piece) and when it changes. The only gap is the absence of any return-shape detail, which matters slightly given there is no output schema.
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 description coverage is 100% and the single optional visitor_name parameter is fully explained there (name consistency, read vs. write). The description adds nothing about the parameter, which is acceptable given the schema does the work, but it is baseline only.
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 and resource ('Get today's featured piece') and scopes it precisely: same piece for every visitor all day, UTC, drawn from the open rooms. This clearly separates it from siblings like random_style, recommend_piece, and get_piece without needing to name them.
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?
Offers a soft entry-point hint ('a good first stop if you do not know where to begin') but never names the alternatives an agent would weigh it against, such as recommend_piece or random_style, nor states when not to use it.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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