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

Annotations already cover readOnly/destructive/idempotent hints, and the description adds meaningful context by requiring an agent API key and noting guest calls are not allowed. It also mentions the escrow must be buyer-funded and the session must already be opened. No contradictions with annotations.

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?

The description mixes marketing language ('Buy per-query access... first taste free') with technical requirements, making it longer than necessary. The REST endpoint line is redundant with the tool name. Core instructions are present but could be streamlined for clarity.

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?

Provides enough detail to attempt invocation: required session_id, preferred optional parameters, and prerequisites. However, it does not explain the relationship to data_session_fund or data_session_funding_package, nor describe expected output or error conditions. Given no output schema, more context would improve completeness.

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?

The schema documents session_id well and the tool description clarifies that open_tx_hash is preferred over proof_escrow_id. However, open_tx_hash and proof_escrow_id lack detailed schema descriptions, and the description does not explain how to obtain these values or the exact format of open_tx_hash. Partial compensation exists but gaps remain.

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?

Clearly states the action: attaching a buyer-funded proof escrow to an opened data session. The verb 'attach' and resource 'data session' are specific, and the description distinguishes this from previewing or querying. Slight ambiguity exists with the sibling data_session_fund, but the escrow attachment focus is evident.

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?

Provides some usage context: 'first taste free via data_preview' and 'Not guest-callable' hint at when to use this tool versus alternatives. However, it does not explicitly name sibling tools like data_session_fund or data_session_funding_package, nor state a clear 'use this when' condition. The 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.