execute_stream

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

The description adds meaningful behavioral context beyond the readOnly and idempotent annotations by stating that code runs in a separate worker thread for security, implying isolation. It also discloses what gets captured, which is useful for understanding the tool's behavior. It does not contradict the annotations.

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 two sentences with no filler: the first sentence states the action and outputs, the second provides the security/isolation context. It is front-loaded and 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?

With no output schema, the description should provide enough detail about return values; it names high-level outputs (emissions, timeline, performance metrics) but not their structure or format. It also doesn't mention error behavior or timeout handling explicitly, though the parameter descriptions cover some of this. Overall it is adequate but leaves room for ambiguity.

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%, with all five parameters individually documented, so the description does not need to repeat parameter-level details. It aligns broadly with the capture flags and timeout but adds no further semantic value 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?

The description uses a specific verb and resource — "Execute RxJS code in an isolated environment" — and explicitly lists what it captures: emissions, timeline, and performance metrics. This clearly differentiates it from the sibling tools, which are about linting, analyzing, detecting leaks, generating marble diagrams, and suggesting patterns.

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 gives clear context for when to use the tool: to run RxJS code and capture stream emissions, timeline, and performance metrics. It does not explicitly name alternatives or state when not to use it, but the context is unambiguous enough for an agent to select this tool over the non-execution siblings.

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