replay_start

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

With no annotations, the description must disclose behavioral traits (e.g., effect on chart, state changes, prerequisites). It only says 'Start replay mode,' offering no information about side effects, required permissions, or what happens to the current chart state.

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 overly terse (single phrase) and lacks structure or explanatory sentences. While concise, it sacrifices informational value, failing to earn its place as a useful guide.

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 lack of output schema and the complexity of a 'start' command that likely alters state, the description is incomplete. It does not explain return behavior, prerequisites (e.g., a chart must be active), or the relationship to sibling tools like replay_status.

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%, with 'to' and 'from' described as 'End timestamp' and 'Start timestamp' in the input schema. The tool description adds no additional meaning beyond these schema descriptions, so a baseline score of 3 is appropriate.

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 'Start replay mode' clearly indicates a verb ('Start') and resource ('replay mode'), which distinguishes it from sibling tools like replay_step (advance step) and replay_stop (stop). However, it lacks detail on what 'replay mode' entails, limiting clarity.

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?

No guidance is provided on when to use this tool versus alternatives (e.g., replay_step for incremental advances) or when not to use it. The description only states the action, leaving usage context entirely implicit.

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