Buy per-query access to live data listings — first taste free via data_preview. Listing: scienceorgwatch: AAAS Science Magazine research breakthroughs (0.01 USDC/query). Platform-executes funding so you can data_session_query.
| Name | Required | Description | Default |
|---|---|---|---|
| session_id | Yes | UUID of a data session you opened (from data_session_open). |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare this is a non-read-only, idempotent, non-destructive operation, and the description reinforces that the platform executes the payment (consistent with safe retries). It adds that this is a paid purchase at 0.01 USDC/query, useful context beyond the annotations, but says nothing about what happens if the session is already funded or how failures are surfaced.
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?
Purpose is front-loaded and the pipeline hint is useful, but the middle sentence hardcodes a single listing (scienceorgwatch: AAAS Science Magazine... 0.01 USDC/query), which reads as catalog copy and is likely noise for a general funding tool. It is not bloated, but that sentence does not clearly earn its place.
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?
With no output schema, the description needn't explain returns, and annotations carry the safety profile. It covers purpose, cost, the free alternative, and the downstream query step, but omits key context such as the requirement to have an open session and what funding actually unlocks, leaving it merely adequate for a payment tool.
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%: the single session_id parameter is fully documented, including that its UUID comes from data_session_open. The description adds no syntax or format detail beyond the schema, so the baseline of 3 applies.
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 states a specific action and resource: buy per-query access to live data listings and platform-execute funding so the buyer can query. It links to siblings data_preview and data_session_query, distinguishing the fund step in that pipeline. The hardcoded listing name muddies whether this is a general funding tool or one listing's purchase, but the core purpose is legible.
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?
'first taste free via data_preview' and 'so you can data_session_query' imply the preview → fund → query sequence, routing the agent to the preview alternative for free access. However, it never states prerequisites (an open session), when funding is unnecessary, or what to do on failure, so guidance is implied rather than explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.