chart_set_session

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

Annotations already declare this is a non-read-only, non-destructive mutation with open-world behavior. The description adds meaningful behavioral detail beyond annotations: it verifies the exact session and resolved symbol, and refuses during replay. It does not describe the return or error behavior, but the annotations cover the safety profile sufficiently.

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 is a single front-loaded sentence with no filler. Every clause contributes either the primary action or a key operational constraint.

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?

Given the annotations and the schema's rich descriptions for most parameters, the description covers the essential behavior and constraints for this mutation tool. It leaves some context unexplored, such as failure modes beyond replay and layout mismatch, but no output schema exists and the remaining schema gaps are minor.

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 75%, with descriptions for session, target_id, and expected_layout_id already explaining exact ID sourcing and mismatch handling. The description reinforces exactness but does not add meaning for timeout_ms, nor does it compensate for the one undocumented parameter.

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 verb and resource: 'Set an advertised native trading session.' It also adds verification constraints, making the operation's purpose clear. However, it does not explicitly distinguish itself from the sibling chart_get_session beyond the verb difference.

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?

The description includes a clear exclusion ('refuse during replay') and implies prerequisites through 'verify exact session and resolved symbol.' Yet it does not explicitly say when to use this tool versus chart_get_session or other session-related siblings, leaving usage partially inferred.

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