IMDb title box office summary: lifetime gross by market, domestic opening weekend, and production budget. A real title with no box office data returns has_box_office false rather than an error.
| Name | Required | Description | Default |
|---|---|---|---|
| id | No | ||
| url | No |
| Name | Required | Description | Default |
|---|---|---|---|
| data | Yes | The tool result payload (shape varies per tool; see each tool's docs resource). |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only and open-world hints, and the description adds genuinely useful behavioral context beyond them: a real title lacking box office data yields has_box_office=false rather than an error. That error-handling detail is exactly what an agent needs and isn't in structured fields.
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 tight sentences, front-loaded with the primary payload and back-loaded with the useful edge-case note. No 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?
An output schema exists so return fields needn't be explained, and the edge-case behavior is covered. However, with two undocumented parameters and no guidance on id vs url, an agent lacks what it needs to invoke the tool correctly.
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 0% for two parameters (id, url), and the description says nothing about either parameter — not what format id takes, not whether id or url is preferred, not whether one is required. The description does not compensate for the coverage gap.
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 ('IMDb title box office summary') and enumerates the exact data returned: lifetime gross by market, domestic opening weekend, production budget. It clearly scopes the tool apart from generic title tools, though it doesn't explicitly name a sibling.
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 implied by the resource (fetch box office data for a title), and it notes the no-data edge case, but it gives no explicit when-to-use vs alternatives guidance or prerequisites for choosing this over imdb_title.
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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