session_start

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does reveal meaningful behavior: automatic injection of relevant context, loading knowledge from all previous sessions, and returning compressed observations. However, it does not disclose potential side effects like session persistence, whether repeated calls create multiple sessions, or any state changes beyond starting a session.

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 well-structured with clear sections for triggers, workflow position, and parameters. The first sentence is a strong front-loaded definition. It is slightly repetitive ('ALWAYS CALL THIS' and 'WORKFLOW POSITION' say similar things) but overall each section 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?

For a tool with no output schema and no annotations, the return behavior is only vaguely described as 'context block with relevant past observations (compressed for efficiency).' It also does not explain how the returned context should be used, what happens when no past context exists, or how this relates to sibling session tools like create_session and end_session. Some gaps remain.

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 description coverage is 0%, so the description fully compensates by explaining all four parameters. session_id is described as a unique identifier, query as the session focus for finding past context, limit as the max observations with a default and tuning advice, and user_id as an optional identifier. This goes well beyond the bare schema.

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 opens with a specific verb and resource: 'Start a new session and automatically inject relevant context from past sessions.' It clearly conveys what the tool does, but it does not explicitly differentiate itself from sibling tools like create_session or join_session, which could overlap in purpose.

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 usage context through 'AUTOMATIC TRIGGERS' and states that this should 'ALWAYS CALL THIS' at the start of any work session, and positions it as the 'First tool to call when starting work.' It clearly says when to use it, but it does not mention any exclusions or alternatives, such as when create_session might be preferred.

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