Rewind a market session

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

Goes well beyond the annotations (destructiveHint=true, idempotentHint=true, readOnlyHint=false) by disclosing what is destroyed (every later checkpoint), the checkpoint cadence and 64 cap, and 'Runs no market', all of which an agent needs before committing to an irreversible step.

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?

Four compact sentences, front-loaded with the core mutation and its destructive consequence, then checkpoint mechanics, alternative, and return shape – every sentence earns 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?

Covers destruction behavior, checkpoint limits, the fork alternative, and return format ('as session_state does') despite an output schema already existing; nothing an agent needs to call it correctly is missing.

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 100%, so both parameters are already documented; the description only echoes the step semantics ('one of the session's checkpoints') without adding format or validation detail beyond the schema.

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 precise verb and resource ('Put an open session back to a checkpoint... by step, and drop every checkpoint after it') with exact scope, clearly separating it from siblings like session_fork and session_state.

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 names the alternative and the condition that selects it: 'To keep the later state as well, session_fork first.' It also points to session_state as the way to list checkpoints, leaving nothing to inference.

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