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

Adds real behavior beyond the annotations: the session appears in the event app for attendees, and the event day is derived from `start` and auto-created if missing — a non-obvious side effect on a parent resource. It also names the underlying endpoint POST /public/api/v1/lecture, but does not mention failure modes or what a rejected payload returns.

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?

Four short sentences, front-loaded with a WRITE marker, then purpose, then the side effect, then prerequisites and the endpoint. No sentence is redundant and the riskiest detail (implicit event-day creation) lands early.

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 15-parameter create tool with no output schema, the description covers purpose, dependency ordering and the implicit event-day creation, which is the information an agent cannot get from the schema alone. It omits any sense of the return value/created id, which matters for follow-up calls attaching speakers or labels.

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 every one of the 15 parameters is already documented in-schema, including enum values, formats, defaults and the workshop-only constraints. The description only echoes the hall/speaker/label id concept ('pass their ids') without adding format or ordering detail beyond the schema's baseline.

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?

Opens with a specific verb and resource: 'WRITE: add a session (lecture or workshop) to the event program.' The parenthetical scope distinguishes it from a break-type entry, but it never names eventee_create_break or eventee_update_session to draw a hard boundary between the three program-item tools.

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?

Clearly states preconditions: 'The hall, speakers and labels must already exist (create them first and pass their ids)' and points to eventee_get_program for hall ids, which tells the agent the correct call ordering. It stops short of saying when to prefer this over the sibling update or break tools.

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