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

Annotations already declare readOnlyHint and destructiveHint, so 'reads only and changes nothing' is partly redundant. However, the description adds genuinely useful context the annotations do not carry: the connected-account prerequisite and the pounds unit for weights.

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-loaded with the usage trigger and example, then the return contents and constraints. Four sentences with little waste, though the read-only statement partly overlaps the annotations.

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. The description covers the auth requirement, unit system, and safety profile, leaving little for an agent to guess, though it does not describe how sessions are ordered or scoped.

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 the single 'days' parameter is already fully documented with its default and range. The description's mention of 'today or the coming days' adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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 (get planned sessions) with a concrete example ('what is my workout today'). It is clearly distinguishable from siblings like get_training_history (past) and get_saved_training.

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?

Explicitly frames when to use it ('when the user asks what their Phorme plan has for today or the coming days') with a sample query. It implies but does not name an alternative for historical data, so it stops short of the when-not/alternatives tier.

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