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

With no annotations, the description carries the full burden and does disclose meaningful authorization behavior: approved apps are public while drafts are visible only to the owner. It omits error behavior for missing/unknown slugs, which is the main remaining gap for a fetch tool.

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?

Three short sentences: what it returns, the visibility rule, and when to use it. Zero filler and the return contents are front-loaded.

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?

There is no output schema, so enumerating returned fields compensates well, and the visibility rule covers authorization. Missing only failure behavior for invalid slugs, which matters little for a simple read.

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 slug and api_key are already documented in the schema, including the note that slug comes from search_apps or create_app. The description adds no parameter syntax or format detail beyond that baseline.

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 gives a specific verb+resource ("Fetch one app by slug") and enumerates the payload (description, tags, links, rating, inspection). The singular "one app" scope contrasts cleanly with the plural list/search siblings such as search_apps and list_my_apps.

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?

It states a clear trigger ("Use it before voting or reviewing"), tying it to the vote and write_review siblings. It offers no explicit exclusions or named alternatives, so it falls short of the top score.

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