create_session

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

No annotations are provided, so the description carries the full burden, and it does: server-side validation with a literal 400 error message, the unknown-course-id failure mode, the max-24-hour and end>start constraints, an explicit prompt-injection warning for topic/notes, and a non-destructive guarantee. Server-side rejection behavior is exactly what an agent cannot infer from the schema.

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?

Purpose is front-loaded in the first clause, followed by ordered operational constraints (id sourcing, completion flag, time validity, injection caution). Sentences are dense but every one carries a distinct, actionable fact with no filler.

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?

An output schema exists, so return values need no explanation, and the description covers every caller-facing decision: where to get the id, how to set is_completed, time validity rules, and safety around free text. Nothing needed to invoke it correctly is missing.

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 must compensate. It documents course_id's provenance (list_courses output, server-validated), is_completed's semantics, the start/end_time ordering constraint, and treats topic/notes as untrusted free text. It leaves course_name and course_color unexplained despite being required, which is the only real gap.

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?

States a specific verb and resource with scope: 'Creates a new study session (calendar entry) in StudyLife for the given course and time range.' The parenthetical disambiguates it from siblings like create_note and list_sessions without the agent needing to open another schema.

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?

Gives explicit prerequisites and routing: 'call list_courses first rather than guessing an id,' and states the exact condition for is_completed=True (already happened, e.g. 'I just studied for 2 hours') vs False (planned/upcoming). This is when-to-use guidance an agent can act on directly.

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