grade_history

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), and the description adds real value beyond them: it discloses that no true history service exists, that values are each item's CURRENT grade paired with graded/submitted dates, and that ordering is newest-first. This manages expectations about data fidelity, which the annotations cannot.

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?

The purpose and the key caveat are front-loaded, and the parenthetical detail (newest first) is efficiently placed. The trailing 'and says so explicitly' is slightly redundant phrasing but not wasted length overall.

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?

With an output schema present, return-value structure need not be described, and the annotations cover safety. The description supplies the crucial limitation and ordering semantics; only an explicit sibling-selection rule 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?

There is a single parameter (course_id) with 0% schema description coverage, so the description carries the burden. It only implies the parameter's meaning via 'for a course' and adds no format, type, or source detail, which is minimal but not absent.

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 specific resource and scope: 'what Nexus exposes about grade changes over time for a course,' which is clearly distinguishable from a point-in-time snapshot. It does not, however, explicitly name the confusable siblings (current_grades, course_grade), so sibling differentiation is left to inference.

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?

Usage is only implied: the emphasis on 'over time' and the caveat about Moodle lacking a grade-history service suggest this is the tool for historical/temporal questions. There is no explicit when-to-use statement, no when-not-to-use, and no direct routing to current_grades or course_grade.

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