session_init

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

With no annotations provided, the description carries the full burden and explicitly states 'Writes nothing, asks the shop nothing, costs nothing.' This fully discloses the read-only, side-effect-free nature of the tool, which is critical for safe agent use.

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, front-loads the core purpose, and uses an effective 'what it does' + 'when to call' structure. Every word adds value; no redundancy.

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 simple read-only informational tool with no parameters and no output schema, the description covers all essential aspects: what information is gathered and the safe call behavior. It could specify the exact return structure, but given the conceptual nature, it is adequate.

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 empty schema requires no explanation. The description naturally handles this by not referencing any parameters. Baseline 4 is appropriate for a parameterless tool.

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 clearly states what the tool does: it provides an overview of available stores, the active store, whether Melbis Shop is running, and where documentation starts. It uses specific verbs and distinguishes itself from session_connect by positioning itself as a pre-sign-in reconnaissance tool.

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 explicit guidance on when to call it ('Look around before signing in') and when to re-call ('call it again whenever the person may have switched store'). It does not name specific sibling alternatives, but the context makes the intended use clear.

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