Explain Course Eligibility

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

Annotations cover the safety profile (read-only, idempotent, non-destructive, open-world), and the description adds substantial behavior beyond them: it warns never to read an empty result as 'no prerequisites', explains OBS is authoritative when cross_check disagrees and that disagreements are reported not resolved, and flags term-only offerings. This is exactly the edge-case disclosure annotations cannot carry.

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?

Front-loads the core purpose in the first clause, then adds behavioral caveats in decreasing priority. Dense but every sentence carries a distinct warning; only the quoted-token style is slightly heavy.

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 not be explained, and the behavioral framing is strong. The gap is that a 6-parameter tool with 0% schema coverage leaves the inputs undocumented, and references to 'cross_check'/'archive_seasonality' are ambiguous between inputs and outputs.

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% and the description explains none of the six inputs (course_code, class_year, program_type, use_obs_history, completed_courses, completed_credits). It instead discusses terms ('prerequisite_status', 'cross_check', 'archive_seasonality') that don't appear as parameters, which risks confusing the agent about what can be passed versus what is returned.

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?

Names a specific verb (explain) and resource (course eligibility/prerequisites) plus the authoritative source (official OBS branch prerequisite table), and distinguishes the tool from the community dataset it cross-checks against. An agent can tell this apart from obs_get_course_prerequisites and get_public_course_prerequisites without opening a 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?

Offers some conditional guidance ('check archive_seasonality even when eligibility alone looks fine') and explains when a status is 'unknown' vs 'no_prerequisites'. However, it never explicitly routes the agent between this tool and the many sibling prerequisite tools (obs_get_course_prerequisites, get_public_course_prerequisites), so the when-to-use decision is only implied.

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