eventsource_messages

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

The description conveys that the tool is read-only and that messages are 'captured', which implies non-destructive access to stored data. However, with no annotations, it leaves out important behavioral context such as whether capture must be active, whether reading consumes/clears messages, or any access prerequisites.

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?

One sentence with zero filler. The important scoping detail ('for a tab') is present and the sentence is immediately understandable.

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?

For a one-parameter read tool, the core call surface is present. Yet with no output schema and no annotations, the expected message shape, capture lifecycle, and any required setup (such as devtools_attach) are left unspecified, so the context is only minimally complete.

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?

The description says the messages are 'for a tab', which lets an agent infer that the single parameter tabId identifies the target tab. But schema description coverage is 0%, and the description does not explicitly define tabId's meaning or expected values beyond the schema's raw integer bounds.

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 names a specific verb ('Read'), a specific resource ('captured Server-Sent Events (EventSource) messages'), and a scope ('for a tab'). It clearly distinguishes this from sibling tools like websocket_messages and network_read by explicitly identifying EventSource/SSE.

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?

There is no guidance on when to use this tool versus alternatives such as websocket_messages, network_read, or console_read. It also does not mention prerequisites like needing to attach devtools first or any conditions under which this tool is appropriate.

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