Validate legacy XGR Session Start

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

With no annotations, the description explains the tool's scope (legacy, low-level) and what it does (validates payload). It implicitly suggests it is a read-only check, but does not explicitly state side effects or error behavior. The context is sufficient for a validation tool, but could be more explicit.

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?

Three sentences, each serving a clear purpose: stating the tool's function, distinguishing from alternatives, and providing a critical usage warning. No unnecessary words or redundancy.

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 validation tool with one nested parameter and no output schema, the description adequately covers when and why to use it. However, it does not describe the expected format of the payload or any constraints, which might be needed for full 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?

Schema coverage is 0% and the description only mentions 'session-start payload' without detailing the object's structure or required fields. The description adds minimal semantic value beyond the generic schema, failing to compensate for the lack of schema details.

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 clearly states it validates the legacy low-level session-start payload. It distinguishes itself from the canonical Workbench handoff schema and specifies it is not for MultiBundle. This provides a specific verb and resource, and differentiates from sibling tools like validate_xgr_session_start_handoff.

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?

Explicitly states when to use (validating legacy payload) and when not to use (for Workbench handoff or MultiBundle). Directs to alternative tools (create_xdala_session_start_handoff) with specific required fields, providing clear usage guidance.

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