get_postcardGet your souvenir postcard: a text, your badges, the rooms you visited and your favorite piece, plus the URL of the postcard image (SVG) to hand to whoever sent you.
| Name | Required | Description | Default |
|---|---|---|---|
| visitor_name | Yes | 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 readOnlyHint, idempotentHint, and non-destructive, so the safety profile is covered. The description adds real value beyond them by disclosing what the response contains (badges, visited rooms, favorite piece, SVG URL) in the absence of an output schema. It does not cover edge behavior such as an unknown visitor_name or whether an empty passport still yields a postcard.
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?
One front-loaded sentence that itemizes the return payload before the sharing use case. Minor ornament ("souvenir", "to hand to whoever sent you") but nothing that could be cut without losing the sharing context.
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 one-parameter, read-only, non-destructive tool with no output schema, the description covers the main gap, what gets returned, and gives the sharing rationale. Only missing piece is behavior on a visitor_name with no history, which matters for interpreting an empty result.
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%, so the single visitor_name parameter is fully documented in the schema, including the 40-char limit and the deterministic name-to-avatar mapping. The description adds no additional parameter meaning, which is the expected baseline when the schema does all the work.
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 clear verb and resource ("Get your souvenir postcard") and then enumerates the exact payload: text, badges, rooms visited, favorite piece, and the SVG image URL. That is far more specific than the title. It stops short of naming a sibling it differs from (e.g. my_passport, which plausibly overlaps on badges), so 4 rather than 5.
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?
Usage is only implied: the closing clause "to hand to whoever sent you" hints at a share/export scenario, and "your badges... rooms you visited" implies post-visit use. There is no explicit when-to-use, when-not-to-use, or pointer to my_passport or my_messages as alternatives, so an agent must infer the routing.
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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