mne_session_info

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

With no annotations, the description carries the full burden. It clarifies that the tool returns a one-line summary of each object, and the verb 'List' implies read-only behavior. However, it does not explicitly state that the operation makes no modifications to the session, nor does it describe any potential performance implications. Adequate for a simple inspection tool but not exhaustive.

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 sentences, front-loaded with the action verb, no redundant phrasing. The second sentence adds practical usage guidance without fluff. Every word 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 the tool's purpose, the content it reports, and the recommended usage context. An output schema exists, so return format details are not required. It could mention that the session persists across tool calls, but that is implied by 'persistent analysis session'. Sufficiently complete for a zero-parameter inspection tool.

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 tool has zero parameters, so the baseline is 4. The description enumerates the object categories in the session, which indirectly informs expected results, but there are no parameter details to add. No further compensation needed.

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?

Description opens with 'List every object currently held in the persistent analysis session' – a specific verb and clear resource scope. The parenthetical enumeration of object types (raw recordings, epochs, evoked, ICA, events, arrays) further clarifies what the session contains. This distinguishes it from sibling tools like mne_list_files or mne_get_info.

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 states the intended use case: 'Use this to see what is loaded before operating on it.' This gives clear contextual guidance. It does not name alternative tools or exclusion criteria, but the tool's unique role as a session-wide listing makes ambiguity low.

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