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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds behavior beyond that: it is the per-turn opening read, and supplying a cursor yields a diff rather than a full board reload — useful operational context, though no details on response size or cursor lifetime.

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?

Two sentences, front-loaded with the open-session framing before the cursor tip, with little wasted wording. The mid-sentence enumerated payload list is dense but each item informs the agent about scope, so it 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 two-optional-parameter, read-only tool with no output schema, the description adequately covers what comes back and how to request incremental results. Minor gaps remain around the default 'lean' behavior and the shape/size of the payload, but the core invocation needs are met.

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 100%, so both parameters are already documented, and the description's explanation of 'since' ('the cursor a previous answer carried') largely restates the schema's own wording. The 'lean' parameter is not addressed in the description at all, so no meaningful meaning is added beyond the 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 states a concrete verb and resource ('Open a session') and enumerates the payload: handbook, connection, bound project's guide, projects and their work, plan budget. That enumeration makes it distinguishable from narrow siblings like get_project or read_connection, though it never names an alternative directly.

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?

It gives clear usage context: 'the read every turn starts with,' establishing this as the bootstrap call, and explains the incremental mode via 'Pass since ... instead of reading the board again.' It lacks explicit when-not-to-use guidance or a named sibling to prefer in other situations.

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