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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely non-structured information: the operation 'Costs 1 credit', which matters for an agent deciding whether to spend a call. It does not explain the caching behavior behind cache_max_age.

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?

Two short sentences, purpose first, returned fields second, cost last. No filler; every clause carries information an agent can use.

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 simple two-parameter read tool with no output schema, listing the returned fields is a useful substitute for a response spec. The gap is the undocumented cache_max_age parameter, whose effect on behavior and cost is left entirely unexplained.

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 coverage is only 50%: 'id' is documented as a numeric Deezer track id, but 'cache_max_age' has no schema description and the description says nothing about it either. The description adds no parameter meaning beyond what the schema already carries.

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+resource (track details) and enumerates exactly what a Deezer track record contains (title, artist, artwork, duration, release date, ISRC, tempo). It is clearly a single-object lookup, distinct from deezer_search or deezer_artistTopTracks, though it never names those siblings explicitly.

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?

Usage is implied: it takes a numeric id, so an agent infers this is the fetch-by-id step after a deezer_search. However, there is no explicit 'use this when...' or 'do not use for...' statement, and no mention of where to obtain the required id.

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