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

Goes well beyond the annotations by disclosing upsert/merge semantics: anything omitted keeps its stored value, with stated defaults (public visibility for a new entry) and the rule that the completion date is preserved. That is exactly the non-obvious mutation behavior an agent needs and annotations cannot convey.

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 action and packs several useful clauses into a compact block with no filler. The trailing 'Requires sign-in' sentence is slightly detached but still 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?

For a mutation tool with no output schema and five parameters, the definition covers prerequisites, defaults, merge behavior, and idempotency, leaving nothing material for an agent to guess before calling it.

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%, so the description must carry the load; it does, explaining slug provenance, what notes/completed_at/visibility mean, defaults, and the status options in prose. Only the slug's allow/format constraint is left to the schema pattern.

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?

Opens with a specific verb+resource ('Add a published adventure ... to the signed-in member's bucket list or mark it as done') and scopes it by slug sourced from search_adventures. An agent can distinguish this from search_adventures and unmark_adventure without inspecting the 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?

States the sign-in prerequisite, where slugs come from, and covers the repeat-call case. It stops short of explicitly naming unmark_adventure as the way to remove an entry, so the when-not guidance is implied rather than stated.

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