In explanations, asterisks (*) indicate anagrams, ellipses (...) indicate selections from clue text, quotation marks (" ") indicate homophones, and lowercase letters indicate deletions.
1. AGENT: ArGENT
2. ALL COMERS: LOCAL*+M(ER)S
3. ANTEFIXES: SEX+IF+ETNA rev.
4. ANTRORSE: A(NTRO)RSE, TORN*
5. ASTRO: ASTOR with OR reversed
6. BERMUDIAN: (A RUM IN BED)*
7. CHINCHILLA: CHIN+CHILL+A
8. CLAPHAM: C(LAP+H)AMe
9. CUNNING: CONNING with U for O
10. DEBRIEF: definition plus pun on DE-BRIEF
11. DRAINED: (tIRED AND)*, &lit.
12. DRUIDIC: D(RU)ID+IC, UR rev.
13. ELECT: ERECT, with L for R
14. HAIR: "HARE"
15. INEPT: T(PEN)I, rev.
16. KOHLRABI: (O..A R..L B..K I..H)*
17. LANFRANC: LANd+FRANCe
18. NATTER: NATTiER
19. PEPPERCORN: double definition
20. PROCEDURES: ...SE RUDE CORP..., hidden rev.
21. RED SEA: SAID RE, Spoonerism
22. REKINDLING: R(EKIN+D..L)ING, NIKE rev.
23. RELIEVOS: RE(LIEV)OS, EROS with R to front, VEIL rev.
24. TIDY: DIrTY*, &lit.
25. TOCSIN: "TOXIN"
26. TSAR: T. S. A. R., initial letters, &lit.
27. TUTU: "TOO TOO"
28. YOU-ALL: YOUA(L)L*, LAYOUt
29. ZAMINDARI: ...ZA MIND ARI..., hidden
The leftover answer, CUNNING, was defined by Philip Dormer Stanhope, 4th Earl of Chesterfield (1694-1773), as THE DARK SANCTUARY OF INCAPACITY, which appears in the perimeter.