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

Annotations already declare readOnlyHint=true, so the safety profile is covered; the description adds real value on top by naming the concrete fields returned (name, SQL text, conn, definitionsUsed) and confirming that executing the query is explicitly out of scope. No cost, latency, or auth detail, but the key behavioral claim is unambiguous.

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, front-loaded with the core action and return payload, then the run_sql disambiguation and the report relationship. No sentence is filler.

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 correctly compensates by listing the returned fields, and it notes the report linkage via fastero_get_report. It does not describe errors for a missing/foreign queryId, which would be the last piece of context an agent might want.

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 both parameters already document where their ids come from (fastero_list_queries, fastero_list_projects). The description adds no further parameter semantics, so the 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 ("Read one saved query") and enumerates the payload it returns: name, SQL text, connection (conn), and definitionsUsed. It explicitly separates itself from fastero_run_sql, which is the sibling an agent would most plausibly confuse it with.

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?

"Nothing is run: fastero_run_sql runs SQL and returns rows" gives an explicit when-not plus the alternative to pick instead. It also implies the queryId comes from fastero_list_queries. It stops short of stating the list-vs-get selection rule outright, so it is strong but not exhaustive.

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