search_registers

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

With no annotations, the description carries the load and does well: it discloses the return shape at field level ('address, name or SunSpec point, type, unit/scale or sf, access') and explicitly states the tool never contacts a device, which is the key safety fact. It stops short of saying what happens with truncation/limit defaults or whether results are ranked, which is the remaining behavioral gap.

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 what is searched and followed immediately by the shape of the results and the escape hatch to get_register. No filler or restated title.

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 search tool with no output schema and no annotations, the description supplies the result-entry fields, the documentation-only guarantee, and the escalation path to the detail tool. Only mild gaps remain (no mention of the default limit of 20 or result ordering), which are partially covered by the schema.

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 100%, so the baseline is 3; the description adds value by spelling out that 'native' means the EMS map and 'sunspec' the SunSpec map, clarifying the intent of the interface parameter beyond its bare enum. It says nothing extra about limit or query syntax, but the schema already covers those with examples.

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 ('search the documented registers') and names the exact scope ('native EMS map and SunSpec map' of the Wattsonic MATIC inverter). It also implicitly distinguishes itself from the sibling get_register by describing its results as 'compact entries', so an agent can tell search from fetch without opening either schema.

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?

Explicitly routes: 'Use get_register for the full record (value list, range, write function, effective conditions, read-back registers, persistence)' — that is a named alternative plus the condition that selects it. 'Documentation only; never touches a device' further tells the agent this is off-device lookup, not a live read.

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