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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds two things the annotations do not: an authentication prerequisite ('free Messe Atlas account, sign in when prompted') and the truncation/scope behavior of the return ('upcoming editions (next 20)').

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 sentences, no padding, and the auth prerequisite is front-loaded before the content description. The second sentence is dense but readable; slightly more structure could separate the identifier form from the returned fields.

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?

With no output schema, the description carries the burden of describing returns and does so at a useful level (city, website, hosted event series, next 20 upcoming editions) while also flagging the auth requirement. It is complete enough to call correctly, though it says nothing about behavior for an unknown slug/uuid or rate limits.

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% and there is a single parameter, so the schema already documents id_or_slug as a slug or uuid. The description's 'by slug or uuid' merely restates that and adds no format, casing, or resolution detail beyond it.

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 ('One venue by slug or uuid') and enumerates the payload scope (city, website, event series, next 20 editions), so it is clearly distinct from search_venues and get_venue_spaces. It does not name those siblings explicitly, which keeps it short of a 5.

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 only implied: 'one venue by slug or uuid' tells the agent this is a single-entity lookup rather than a search, and the account requirement sets a precondition. There is no explicit statement of when to prefer this over search_venues or get_venue_spaces, nor any exclusion guidance.

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