session_primer

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

Annotations already indicate readOnlyHint=true, so the tool is a safe read operation. The description adds that it 'restores context from the previous session,' which is useful but does not provide additional behavioral details beyond the annotation.

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 extremely concise with two short sentences. The key action and usage timing are front-loaded, and every word contributes to the meaning without 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?

Given no parameters and no output schema, the description is mostly complete. It states the purpose and when to call. However, it could mention what the tool returns or that it can be called safely multiple times, but for a simple read operation, this is sufficient.

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 input schema has no parameters, so schema description coverage is 100%. With zero parameters, the baseline score is 4, and the description does not need to add parameter information. It fulfills this baseline adequately.

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 the tool's purpose: reading the most recent session handoff primer to restore context. It specifies the verb 'read' and the resource 'session handoff primer', which distinguishes it from sibling tools like 'session_handoff' or 'start_handoff' that likely write or initiate handoffs.

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 explicitly says 'Call at session start,' providing a clear usage context. While it does not mention when not to use or alternatives, the context is well-defined and sufficient for an AI agent to know when to invoke this tool.

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