shared_margin_begin

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

No annotations provided, so description bears full burden. Only states action with no disclosure of side effects, response format, or prerequisites. Fails to explain what 'start' entails (e.g., creation of session record).

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?

Single sentence, front-loaded with purpose, no extraneous information. Efficient for agent parsing.

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?

No output schema, but description does not explain return value or session behavior. Lacks integration context with sibling tools, leaving agent unsure about workflow steps.

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 67% (2 of 3 parameters described). Description adds no parameter info beyond schema. Missing description for 'mediaType' is not compensated, but schema enum values partially clarify it.

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?

Description uses specific verb 'Start' and resource 'durable co-reading, co-viewing, or mixed shared-attention session', clearly indicating the tool's function. Differentiates from siblings like shared_margin_capture and shared_margin_finish by being the initiation step, but does not explicitly highlight the distinction.

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?

No guidance on when to use this tool versus alternatives. Does not provide context for session lifecycle or when to invoke sibling tools like shared_margin_capture.

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