Session instructions

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

The annotations declare readOnlyHint=true, implying read-only operations, but the description lists actions like push, clear, ack, and checkpoint, which modify state. This contradiction undermines transparency. Additionally, the description does not disclose important behavioral traits such as persistence, versioning, or concurrency handling.

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 concise but lacks structure. It efficiently lists actions but does not organize them meaningfully or separate the summary from details. A bulleted list or grouping by operation type would improve clarity.

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 the tool's complexity (8 actions, 9 parameters, no output schema), the description is insufficient. It fails to explain the purpose of each action, the nature of the instruction cache, error conditions, or return values. This leaves the agent with significant gaps in understanding.

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 100% description coverage, so the description does not need to repeat parameter details. However, it adds no extra context about parameter usage interdependencies (e.g., which parameters apply to which actions).

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 identifies the tool's domain ('Session-scoped instruction cache operations') and lists specific actions, making its purpose understandable. However, it could be more precise by stating what the tool achieves overall (e.g., manage instructions) rather than just listing actions.

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 provides no guidance on when to use this tool versus alternatives like 'session' or 'context.' It does not specify when not to use it, such as when direct modifications are not needed.

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