get_search_index_definition

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

Annotations declare readOnlyHint=true, and the description adds genuinely new behavior: the both-or-neither parameter constraint with its rationale (same index name can exist in different scopes, so location must be explicit, not guessed) and the failure mode returning {'success': False, 'error': ...}. The enumerated return keys are somewhat redundant since an output schema exists, which keeps this below a 5.

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-loaded with the one-line purpose, then the location rule, then the return contract. Well organized and mostly dense, though the long enumeration of return keys is low-value given a declared output schema and could be trimmed to the error case.

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 three-parameter read-only lookup with an output schema, the description covers everything an agent needs to call it correctly: what it fetches, how to specify location, what makes a call invalid, and how absence manifests. Nothing material is 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 0%, so the description must carry the parameter burden, and it largely does: it defines the semantics of bucket_name and scope_name as a coupled location pair, explains the 'omit both' default meaning cluster-level, and states that partial specification is invalid. index_name is only implicitly characterized (the index to look up) with no format hints, which is the main residual gap.

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 ('Get the full definition of a single Search (FTS) index'), which cleanly separates it from list_search_indexes and the SQL index siblings. An agent knows immediately this is a single-object lookup, not a listing.

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?

Gives an explicit, actionable rule for the alternative location modes: pass both bucket_name and scope_name for a scoped index, omit both for a cluster-level index, and only-one is invalid. It also points to list_search_indexes to confirm name and location before calling. What it lacks is a direct 'use X instead when' routing statement against the listing sibling, but the prescriptive confirmation step effectively covers that.

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