opencode_reply

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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the agent knows this is a mutating operation. The description adds little beyond the name, only restating 'follow-up message to an existing session.' It does not explain side effects, append behavior, or auth/rate limits. With annotations present, a score of 3 reflects that it adds minimal contextual value.

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?

Two concise sentences: the first states the purpose, the second gives usage context. Every word earns its place and the key action is front-loaded.

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?

With an output schema present, annotations covering side effects, and full parameter descriptions, the description fills the remaining gap by linking to sibling tools. It is complete enough for correct invocation, though it could optionally mention that it appends to conversation history, but that is implied by the destructive hint.

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 description coverage is 100%—each of the 8 parameters has a clear description in the schema. The tool description does not add any parameter-specific meaning beyond what the schema already provides, so the baseline 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 states a specific action—'send a follow-up message to an existing session'—and explicitly ties it to conversation starters (opencode_ask, opencode_session_create). This clearly distinguishes it from sibling tools like opencode_session_create or opencode_message_send.

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?

It provides clear usage context: 'Use this to continue a conversation started with opencode_ask or opencode_session_create.' This tells the agent when to use it, though it does not enumerate alternatives or exclusions, so it earns a 4 rather than a 5.

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