context_open

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

With no annotations, the description carries the full burden and does so well. It discloses that the tool both starts and resumes, that it returns previously stored content, and that resuming after a restart surfaces prior knowledge. These are non-obvious behavioral details beyond what the name or schema alone could convey.

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?

Three sentences with no filler: the core action is front-loaded, followed by a concrete usage condition and a behavioral outcome. Every sentence contributes essential information an agent needs before calling the tool.

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?

Despite lacking an output schema and annotations, the description explains what the tool returns when resuming, when it should be called, and how to manage session_id. This is sufficient for an agent to select and invoke the tool correctly in a long-running task workflow.

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?

Schema coverage is 100%, so the baseline is 3, but the description adds real operational meaning to session_id by stating it must be reused consistently across calls. It reinforces the schema's existing description without restating it verbatim, adding value for the agent's invocation strategy.

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 uses a specific verb phrase, 'Start or resume a named memory session,' which precisely identifies the resource and action. This clearly distinguishes it from siblings like context_append, context_recall, and context_list_sessions without requiring the reader to infer meaning.

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 explicit when-to-use guidance: call once at the beginning of long-running tasks and reuse the same session_id for later calls. It does not explicitly name alternatives or state when not to use it, but the context is clear enough for an agent to decide correctly.

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