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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds the conceptual meaning of each goal type (e.g. 'frequency (per week)', 'load (target kg in one exercise)'), which the annotations do not provide, but it says nothing about duplicate handling, validation failures, or whether the goal is editable afterward.

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?

A single front-loaded sentence with zero filler; the type meanings are packed into parentheticals rather than spread across paragraphs. Slightly dense as a fragment, but every clause 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?

With 7 parameters, no output schema, and a mutation that is not destructive, the description covers the type dimension adequately but omits relationship context an agent would need: how this differs from update_goal, whether goals can coexist, and what is returned on success. Adequate but with clear gaps.

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 86%, so a baseline of 3 applies, but the description genuinely adds meaning the schema lacks: the enum members are undocumented in the schema, and the description defines each one (workouts = count, frequency = per week, load = kg on one exercise). It does not add anything about start_date/end_date semantics, which the schema already covers.

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 plus resource ('Creates a goal') and immediately enumerates the four supported goal types, so an agent knows exactly what will be created. It does not differentiate itself from siblings like update_goal or set_weekly_target, which is the only reason it falls short of a 5.

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?

There is no guidance on when to use this versus update_goal, set_weekly_target, or list_student_goals, and no mention of prerequisites (e.g. that studentId must come from list_students) or what happens if a goal of the same type already exists. Usage is only inferable from the verb 'create'.

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