Icu Get Activity Messages

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered by structured data. The description goes meaningfully beyond that by disclosing return ordering (chronological), message fields (author, content, timestamp, seen-flag), and the non-obvious tombstone behavior where deleted notes persist as "(deleted)" placeholders with a deleted timestamp — that last detail is real behavioral value an agent could not infer.

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 core purpose, then the READ/WRITE disambiguation mnemonic, then trigger phrases, then return shape. Every sentence earns its place; the parenthetical mnemonics are compact disambiguators rather than 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 the description doesn't need to detail return values — yet it still summarizes ordering and the deleted-placeholder quirk, which is exactly the edge case that would otherwise surprise an agent. For a one-parameter read tool with full annotation coverage, nothing needed 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?

Single parameter with 100% schema description coverage ("The Intervals.icu activity ID"), so the schema carries the semantics. The description's phrase "a specific activity" reinforces but adds no format, ID-source, or validation detail beyond the schema; 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 ("Read the notes and comments attached to a specific activity") and explicitly contrasts with the write sibling via the "plural = READ" / "singular = WRITE" mnemonic. An agent can distinguish this from icu_add_activity_message, icu_update_activity_message, and the activity-detail siblings 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?

Gives three concrete user-phrasing triggers ("what did my coach say about that ride?", "show me the comments on yesterday's run", "any feedback on this workout?") and names the correct alternative tool for the write case. When-to-use and when-not-to-use are both explicit.

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