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

Annotations already declare destructive=false, idempotent=true, readOnly=false, so safety and repeat-call behavior are covered. The description adds useful mechanism context ('Platform-executes funding') and a concrete price (0.01 USDC/query), but omits what happens on insufficient balance, whether the charge is reversible, and how funding relates to escrow.

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?

Front-loads the core action, which is good, but the embedded hardcoded listing name and price read as volatile example data that will stale quickly and bloat a one-parameter tool's description. The 'so you can data_session_query' clause is terse to the point of being ungrammatical.

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?

No output schema exists, so the description must convey enough to act on, and it does give the cost model and the platform-executed funding mechanism. Remaining gaps (authorization/wallet requirements, relationship to escrow and funding-package siblings) are moderate but not blocking.

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?

Only one parameter and schema description coverage is 100%, with the schema itself explaining the UUID comes from data_session_open. The description adds no format or sourcing detail beyond that, 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?

States a specific action ('Buy per-query access to live data listings') on a specific resource (a data session), and names the downstream sibling it enables (data_session_query). It is distinguishable from data_preview (free taste) but the hardcoded listing blurb muddies the core purpose.

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?

It implies a workflow: try data_preview free first, fund here, then data_session_query. However it never says when to choose this over the closely-named siblings data_session_funding_package or data_session_attach_escrow, nor what prerequisites (an open session, wallet balance) must hold.

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