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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, not open-world), so the bar is lower. The description adds genuinely useful context beyond them: a free Messe Atlas account is required and sign-in is prompted on demand, plus it discloses what comes back (bio and the session list with event/edition/year/title).

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 tight sentences with no filler, and the payload contents are front-loaded into the same sentence as the lookup. The auth caveat leads, which is slightly less important than the purpose but still compact enough to be efficient.

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 steps in to name the returned fields (bio plus sessions with event, edition, year, title), and the auth prerequisite is disclosed. For a one-parameter read tool this is close to complete, with only explicit sibling routing 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?

Schema description coverage is 100% and the single parameter is already documented as the slug or uuid returned by the search tools. The description's 'by slug or uuid' restates the schema rather than adding format or validation detail, so 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 ('One speaker by slug or uuid') and enumerates the returned payload (bio, sessions spoken at with event/edition/year/title), which clearly separates it from the search_speakers sibling. It does not name the sibling explicitly, so it stops 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?

The description implies a single-entity lookup keyed by an identifier obtained elsewhere ('by slug or uuid'), and the auth prerequisite is stated. However it never explicitly says when to use this versus search_speakers or list_edition_sponsors, leaving routing to inference.

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